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Coastal Overview for Land's End to Isles of Scilly

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What is the route?
This is the Coastal Overview for Land's End to the Isles of Scillies. Detailed coastal overviews are intended to be read alongside local area charts so that the key considerations may be noted and pencilled in well in advance. The intention is not only to make passages safer, by highlighting coastal dangers, but also to make them more enjoyable by unavailing all the Havens along the way so that the occasional coastal gem might not be overlooked. This route joins directly with St Mary's Sound to St Mary's Harbour Route location leading into the principal harbour and town of Scilly.

Why sail this route?
This is the primary coastal overview for vessels cruising the Isle of Scillies providing coastal overviews and the directions for the outlying dangers between Land's End.

Tidal overview
Today's summary tidal overview for this route as of Thursday, February 29th at 05:29. There is only a 3-hour window of fair west-going tide from Land's End to the Scillies. This then turns to cross tides setting northwest to north. Departing the Scillies there is a window of 6-hours of an eastward stream.

Scillies east-going

(HW Dover +0500 to -0500)

Starts in 00:50:05

(Thu 06:20 to 08:45)

Runnel Stone west-going

(HW Dover -0200 to +0100)

Starts in 05:59:05

(Thu 11:29 to 14:29)

What are the navigational notes?
Please use our integrated Navionics chart to appraise the route. Navionics charts feature in premier plotters from B&G, Raymarine, Magellan and are also available on tablets. Clicking the 'Expand to Fullscreen' icon opens a larger viewing area in a new tab.

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Please zoom out (-) if all of the waypoints are not displayed.
The above plots are not precise and are indicative only.


The Scilly Isles comprise a group of isles and numerous above and below-water dangers that occupy a bank, about 10 miles long northwest/southeast and 5 miles wide, that lies about 21 miles westward of the Land's End. The largest isles are concentrated in the northeast part of the bank and the small isles, rocks, and hidden dangers intersperse, rather sporadically, the southwest part of the bank. The group consists of 48 islands of which only 5 are inhabited, six if Gugh is counted separately from St Agnes, which are St Mary's, St Agnes, St Martin, Tresco, and Bryher, the others are more or less barren. Hugh Town, the principal settlement, is on St Mary's Island. The rocks in their vicinity, above and below water, are too numerous to describe and keen attention to charts is essential.

Isles of Scilly
Image: Image courtesy of the Earth Science and Remote Sensing Unit, NASA Johnson
Space Center

The island's position produces a place of great contrast with the sea, greatly influenced by the Gulf Stream, means they rarely have frost or snow, which allows local farmers to grow flowers well ahead of those in mainland Britain. The chief agricultural product is cut flowers, mostly daffodils.

Wildflowers Scilly
Image: Visit Isles of Scilly

Exposure to Atlantic winds also means that spectacular winter gales lash the islands from time to time. This is reflected in the landscape, most clearly seen on Tresco where the lush Abbey Gardens on the sheltered southern end of the island contrast with the low heather and bare rock sculpted by the wind on the exposed northern end.

Tresco's lush Abbey Gardens standing in contrast to the baron north end of the

Image: Michael Day via CC BY-NC 2.0


For people who have spent most of their cruising in the English Channel, the Isles of Scilly represent a very different experience. For Scilly is the full Atlantic experience but due to the close proximity to the major landmass, it does not shed the complications of strong tides, sudden weather changes and large scale commercial shipping that includes crossing the Land's End Traffic Separation Scheme (TSS). So the short voyage out from The Channel will be a very new sailing experience for many. One that also requires a measure of determination as the prevailing winds typically make it a beat Down Channel from the major boating centres of the English south coast. Scilly, on the other hand, is a beam reach from France and, perhaps on account of this, Scilly sees as many European boats as English boats during the season.

Rocky outcrops of Scilly
Image: Visit Isles of Scilly

The islands themselves are also something that would be more familiar to the sailors of Brittany than that of the English south coast. The archipelago is an outlying portion of the coarse-grained granitic mass of Cornwall, eroded, partly drowned and clearly defined by the 40 and 60-metre submarine contours. The central island group is composed of 150 outcrops of which 48 are described as islands or islets, and the remaining rocks and ledges cover an area of about 47 square miles. Outside of the five inhabited islands, there is a further handful of sizable practically barren islets. After this, the rocks and ledges above and below water are too numerous to describe. Most are unmarked, difficult to locate and have large areas of shallow water between them. Strong rotary tidal streams surround the islands and often unpredictable localised tidal streams run between them. Finally, and critically important, the island group has no single all-weather, all tide port of refuge that will provide safety in bad conditions.

Scilly gig racing reaches back to a time when competing pilots raced to
approaching ships to secure the fee

Image: Visit Isles of Scilly

So this is an area where a navigator must be highly alert and it only provides a good destination to approach when conditions are right. Newcomers should avoid approaching Scilly at night and plan all arrivals to be in daylight hours when everything is visible, including lobster pots, and with plenty of time in hand should the planned initial berth not be suitable.

Plan to arrive in Scilly in daylight with ample time in hand should a move be

Image: Visit Isles of Scilly

Above all, never make an approach in bad weather. Laying in open water, at a junction of five international shipping routes and in an area subject to poor visibility, Scilly has taken their toll on vessels down through the centuries. The estimated total since records began, in the late medieval times, is an estimated total of 900 ships lost ina nad around its rocks. As such Scilly has one of the highest concentrations of shipwrecks in the UK and there is no need to add to that number.

Round Island as seen during a March storm
Image: Visit Isles of Scilly

Weather information services for this sea area are excellent but should a vessel be caught out it will be best to retreat to Penzance Click to view haven or Newlyn Click to view haven in Mounts Bay, the closest Channel ports of refuge. A vessel coming from the north may find some shelter at anchor on the north coast at St Ives or on the south coast of Ireland. Vessels arriving from France have a wide range of options along the northern coast of Brittany. With all these fall back options nearly a day's sail away, planning a visit to avail of a good weather window is essential.

Blissful sailing on crystal clear waters in good conditions
Image: Visit Isles of Scilly

The reliability of GPS’s perfect position and excellent charts/plotters have transformed the experience of sailing Scilly. However, they cannot be relied upon in isolation to circumvent the numerous rocks and shallows. They work best alongside a watchful eye from the helm with a pair of binoculars, a hand bearing compass and a reliable and well-calibrated depth gauge. Do not let this sound in any way discouraging as the water here is crystal clear. Large sections between the islands are over white sand where the ledges and rocks have a large amount of weed that clinging to then. So everything is highly visible.

Anneka's Quay Bryher and the remarkably clear waters of Scilly
Image: Michael Harpur

Expect the recommended leading marks around the island group set out on Admiralty charts to be very difficult to identify. Visibility often makes these distant historic charted transits indistinguishable. Even with the best of visibility, picking out the historically marked transits can prove challenging. These served mariners who were, as often as not, familiar with the waters and searching for the marks from high decks with telescopes. This is very far removed from the current newcomer trying to pick them out from low slung leisure craft. The identification of rocks and islets that make up transits can also be somewhat frustrated in Scilly by numerous rocks having a tendency to look very similar and have odd and often repeated names.

Great Minalto and Mincarlo as seen off transit from Garrison Hill
Image: Michael Harpur

For instance, in the case of Saint Mary's Sound, which most visitors use for their primary approach, there are two local Gilstone rocks. The particular hazard for the approach that lays off Peninnis Head and another one four miles southwestward in the Western Rocks that has claimed some prominent wrecks. Duplication of rock names is very common throughout Silly with 'Round Rock' being a firm favourite with a dozen mentions, 'Biggal' with almost half that number and the 'Chinks' will feature in at least two separate well used cuts. The relaxed convention also extends to ledges with four of them going by the name 'Tearing Ledge'. Even when the names are different they can be misleading, as with the case in hand, Saint Mary's Sound, the front 'Great Minalto' is a much smaller rock than the rear 'Mincarlo'.

The summit of Great Ganilly just open north of Bant’s Carn Point
Leading through Saint Mary's Road

Image: Michael Harpur

As often as not, trying to pick out and positively identify these transits may serve to add an unnecessary degree of anxiety to the navigation. Particularly so in the Saint Mary's Sound example which is a very well-marked commercial channel where the marks can be relied upon. These factors cause the historic charted transits to be very rarely used today.

A measure of the lack of utility for St Mary’s Sound readily presented itself during the authors two weeks of research for eOceanic. I interviewed three professional skippers from St Mary's Boatmen's Association about these principal Admiralty transits for Saint Mary's Sound and Road and they were all at a loss. This was despite the fact that they crossed their lines several times a day on the consoles of their plotters immediately in front of them. Of course, they used their own marks and know the area better than the backs of their hands, but if the range marks could prove useful they would have known them.

Positively identifiable marks are plentiful in Scilly
Image: Michael Harpur

Their general consensus for St Mary’s Sound was that many of these historic transits only serve to add a measure of unnecessary concern to a newcomer. The best advice for the principal passages such as Saint Mary's Sound is to use the channel as marked by the buoys or fixed artificial marks that can be more positively identified. If, on the other hand, a decision is made to navigate by prescribed transits on natural features in Scilly, keep a sharp eye to the depth gauge and use the binoculars and hand bearing compass. Be absolutely positive in the identification of any marks selected and check the bearings making appropriate allowances for the magnetic variation to confirm.

However, using marks in conjunction with other means of navigation will prove very useful in Scilly. Tidal streams and wind-driven currents create streams that are not easily predicted. Many of these run across principal channels so the use transits as reference points to guide the helm will prove more than helpful.

Never follow a St Mary's Boatmen's Association ferry
Image: Visit Isles of Scilly

Finally, do not be tempted to follow the local St Mary’s Boatmen’s Association ferries and trip boats. More often than not they will be seen cutting many of the corners listed on this route. But the boats are surprisingly shallow, most notably the Bryher ferry. Despite the LOA and passenger carrying capability, it draws a little over a half metre. The helm also avails of deep and intimate knowledge of these waters ad cut through tight channels within meters of covered rocks. Follow these boats at your peril.


Apart from Land's End Traffic Separation Scheme (TSS), the primary dangers on the approaches from England’s south coast are Wolf Rock and The Seven Stones. Wolf Rock is a hazardous a steep-to half-tidal rock, steep-to, lying 8 miles south by southwest of Land’s End. Wolf Rock is awash at high water neaps and there is 60 metres of water within one mile of the Wolf Rock on all sides, and 50 to 66 metres between the rock and the land.

Wolf Rock Lighthouse
Image: Alvaro via CC ASA 4.0

The lighthouse on the Wolf Rock is 41 metres from base to vane, is circular of grey granite, and exhibits a light from an elevation of 34 metres above Mean High Water, Fl 15s which should be seen in clear weather from a distance of 16 miles. The remarkably beautiful tower dates back to 1869 and the lighthouse achieved worldwide publicity in 1972 as the first rock lighthouse to have a helideck constructed on top of the lantern housing.


The Seven Stones are a large cluster of dangerous rocks on a bank that lies 6½ to the northeast of the Isles of Scilly. One mile in extent with some drying at low water and all covered at high water, they lie in northwest/southeast direction. In rough weather, the breakers upon them may be seen from a considerable distance. Lying low and nearly in the fairway between Scillies and the Land's End they are particularly dangerous.

Sevenstones Light Vessel
Image: Maria Fowler

The Seven Stones rocks are marked by 'The Sevenstones' Light vessel that is moored about 2 miles northeast of The Sevenstones and about 10 miles northeast of the Isles of Scilly. The unmanned vessel is painted red, with the words 'Sevenstones' on her sides, Fl (3) 30s, Fog Signal Horn (3) 60s, the range of light 15M and is one of the most likely seamarks of the group to be first seen on an approach from Land’s End.

When navigating between the Scilly Isles and Land’s End, vessels should not pass between Seven Stones and this lightship and should never attempt to pass close to their position. If there is any concern that the tide is pushing a vessel towards The Sevenstones the TV Tower on St Mary's between the hills of Great Ganilly, bearing 234°T, and open South of Hanjague, leads southeast of the Stones towards a Crow Sound entry. The TV Tower in line with the southeastern tip of St Martin’s, bearing 218°T, leads northwest of The Sevenstones and on to Round Island and Old and New Grimsby Sounds.


The Isles of Scilly are very low lying and normally difficult to sight until close to. They usually can be seen at the distance of 15 miles in clear weather and by night by the group’s three lighthouses.

Bishop Rock:The Bishop Rock lighthouse stands on the south-westernmost of all the dangers of the Scilly group. It is conspicuous granite tower, 49 metres high that stands on a rock that is the north of a small detached group of above-water rocks which are mostly awash at high water. It exhibits a light that Fl(2)15s at an elevation of 44 metres above high water, which should be seen in clear weather from a distance of 20 miles in any direction. Bishop Rock is generally the first sighting made when approaching the English Channel from the west.

Bishop Rock Lighthouse
Image: Lucy Rickards

Round Island: The northmost isle of the group Round Island is a low rounded island, from all angles, and surrounded by rocks. Round Island Lighthouse is built atop a 40 metre mass of granite, standing on its north side marking the most northerly outpost of the Isles of Scilly. Round Island Light is shown from a prominent tower, 19 metres high, Fl 10s which should be seen in clear weather from a distance of 18 miles but the light is obscured on some bearings.

Round Island Lighthouse marking the north end of the Isles of Scilly
Image: Michael Harpur

Peninnis Head: Peninnis Head Light, standing on Peninnis Head, at the southwest side of St Mary’s, is made up of a 14 metres high circular skeletal metal tower lower half, with a closed tower upper half balcony and lantern. It has a black lower part with a white upper part and exhibits a light that is 36 metres above high water springs, Fl 20s and can be seen for 9 nautical miles.

Peninnis Light on Peninnis Head, St Mary's Island
Image: Michael Harpur

Peninnis Head Light superseded the old conspicuous lighthouse that stands on its summit of St Agnes. The lighthouse is disused, no longer contains a light, but it still serves as a daymark for the North West Passage.

The old disused lighthouse standing on its summit of St Agnes
Image: Michael Harpur

When in-line with a pointed stone wall, white with a black stripe and situated ½ a mile in front on Tins Walbert islet, it provides the range mark bearing for the pass, of 127° T as best seen on a chart.

Pointed stone wall on Tins Walbert islet (as seen from St Agnes)
Image: Tim Dobson via CC BY-SA 2.0

A conical stone beacon, or daymark, stands on Chapel Down the highest and easternmost point of St Martin. It stands at an elevation of 56 metres and is a rendered granite circular tower 4.8 metres in diameter and 6.4 metres high, set back to conical termination making it 11 metres high, painted with alternate red and white horizontal bands.

Daymark standing on Chapel Down the easternmost head of St Martin
Image: Michael Harpur

This beacon, together with several radio masts and a conspicuous television tower stand on the northwest side of St Mary’s and can be seen from a considerable distance in clear weather. The central TV tower, with a prominent coast guard station standing close south, can be seen from almost all parts of the group.

The TV tower serves to point out the northwest corner of St Mary's throughout
the island group

Image: Michael Harpur

These key marks may be seen in clear weather from a distance of 15 miles, though the first object which appears above the horizon when approaching from the south is the telegraph tower on St Mary's Island. Particular attention is however required by vessels approaching from the southwestward and westward, by reason of the rocky ledges which project in those directions. The Crim and Bishop, the westernmost rocks of the Scilly Isles, are always above water, and on the latter has a stone lighthouse.

The rocky ledge called Pol Bank, with a least depth of 23 metres constitutes the most southerly danger in the Scilly Isles area. It should be avoided by all vessels, especially in periods of heavy swell, when strong overfalls are formed. The Poll Bank is surrounded by deep water and is in fair weather presents no danger other than to open boats.

The Western Rocks as seen over St Agnes
Image: Michael Harpur

The southeastern shores of St Agnes, St Mary's and the Western Islands may be approached as near as a ½ mile, as there are no dangers outside that distance. To the southeast and southward of St Agnes, there is an overfall, between 4 hours flood and 2 hours ebb, occasioned by the confluence of the two streams of the tide at that period.

A Traffic Separation Schemes (TSS), is situated west of the Scilly Isles, south of the Scilly Isles, and between the Scilly Isles and the English coast as may best be seen on a chart. Though traffic is less than what is experienced in the English Channel it is nevertheless significant and vessels should cross the TSS lanes at a right angle.


St Mary's Harbour
Image: Michael Harpur

The heart of the group is the central Saint Mary's Road that lies between the islands of St Mary's, St Martin’s and that of Samson. Saint Mary's Harbour and Hugh Town, its principal town, largest settlement and administrative centre, lies to the east of Saint Mary's Road near the southwestern end of St Mary’s Island. This is fronted by the natural bay of St Mary's Pool. It is further protected to the west by the quay of Saint Mary's Harbour that also serves as a breakwater for the inner harbour area.

Hugh Town may be the principal town of the group but it is very quiet and

Image: Visit Isles of Scilly

All these factors combine to make this the normal initial point of arrival into the group and there are five distinct entrances to Saint Mary's Road. When approaching any of these and the islands as a whole, it is essential to keep a sharp eye out for lobster pot buoys

St Mary's Sound, Broad Sound and the North West Passage are marked and are the easiest to navigate. Crow Sound is also easy to access, but the channel over Crow Bar leading to St Mary's road can dry to 0.7 metres and is only available for vessels carrying any draft at half tide or above. We provide routes to assist in identifying and using all the key passes save for Smith Sound.

Though deep, Smith Sound is narrow unbuoyed, fringed by many unmarked rocky shoals and its leading mark of the summit of Castle Bryher, 23 metres high, between the summits of Great Smith, 8 metres high, on 351°T, is distant and difficult to distinguish. It is, therefore, best addressed with the benefit of local knowledge. Being a poor substitute to St Mary's Sound, to which it offers no advantage and only adds additional risk, we have decided not to provide routing information for this sound.

Yacht approaching St Mary's Sound
Image: Michael Harpur

Although we have linked this Coastal Overview directly to the primary St Mary's Sound to St Mary's Pool Route location we do not want to suggest this is the defacto approach that should be taken to St Mary's Road. Alternative approaches can be made, given suitable weather and state of tide, via Crow Sound to St Mary's Pool Route location from the east and the Scillonian III passenger ferry takes this path at high water. Likewise, Broad Sound or the North West Passage provide well-marked approaches from other directions. In good conditions, they provide excellent entry points.

Scillonian III turning to exit via Crow Sound
Image: Michael Harpur

Whichever route is taken it is essential to arrive in daylight with plenty of time to berth. Leave enough time to change the initially planned berthing location should it subject to swell or uncomfortable winds. Even the principal port of St Mary’s Pool cannot be relied upon all the time - see below. It is not the best berth of the group by any measure and it is particularly uncomfortable in strong north-westerlies. Moreover, its buoys may have already allocated during high season, July to August and particularly the latter when the French come in droves.

Busy yachts on moorings New Grimsby Sound
Image: Michael Harpur

Once the initial primary berth has been reached there are several internal routes available between the islands that provide access to its various anchorages without the need to go to sea. These are usually available at half tide or above and with least depths of about 0.5 metres, sometimes by using side channels as in the case of circumventing the sand spit in the Tresco Channel, these should not prove overly limiting. Particularly so during Neaps when, with a tidal range of 2.3 – 5 metres, they are a reasonably available option for most vessels most of the time. Here are some key internal cuts we have already provided routes for:

As touched on next, in a group where no anchorage provides complete protection, all of the time, and vessels have to prepared to shift in order to make the best of the weather, these internal quicks cuts between anchorages can prove more than useful. Using the key waypoints and moving between Crow Sound to Tean Sound Route location and Old Grimsby Sound from St Mary’s Road Route location opens up access to all the havens to the northeast, east as well as connecting to St Mary's Road.

Likewise, in good conditions, with sufficient rise of tide, preferably flooding, those may also be used as minor approaches from seaward when used in conjunction with the following:


All boats visiting the Isle of Scilly should be aware that this is as close to berthing in the Atlantic Ocean as possible and Scilly lacks a single location that can be considered secure in all weather. So the visit will be an introduction to the all-pervading Atlantic groundswell that is usually at its worst towards high water when the winds are at their lightest. Worse, calm weather does not necessarily mean a calm sea in Scilly as an Atlantic storm a thousand miles away can create long-distance swell that may well arrive in at a different direction to the wind experienced in the group at that time.

Vessels that can take to the bottom will make the best of Scilly
Image: Michael Harpur

So without the advantage of a shallow draft that can tuck right in, or even better, a vessel that can take to the bottom, there's no escaping the fact that a visitor has to be prepared to shift berths and might be unlucky and suffer a rolly, but not unsafe, night or two during a cruise. But even those that can dry are subject to the swell during the period before getting solidly down, or up when re-floating. Get that wrong in a lump and keels and/or the rudder can get damaged and they need to plan the timing and location very carefully to avoid problems. So there is no absolute bullet-proof solution, just the old sailing maxim plan for the worst and hope for the best.

Islander moving about during the season
Image: Visit Isles of Scilly

The key to having the best experience is to continuously monitor for weather changes, move before the situation deteriorates to a location that suits the new conditions. Then, once there, be prepared to lift the hook and vacate at a moment’s notice should there be the least hint of a wind shift or the sudden appearance of any swell from an exposed direction.

Fortunately, all of Scilly’s berths are uniquely beautiful and the distances between them are not great. This is especially the case at half tide, or above, during daylight when the internal channels become available. This is particularly the case during Neaps when, with a tidal range of 2.3 – 5 metres, these options become increasingly available. The principal anchorages and their protected wind and swell directions are as follows:

  • St Mary’s Pool Click to view haven (St Mary's) - Good in all weathers except west by northwest, west-northwest, northwest, and north-northwest.

  • Porth Cressa Click to view haven (St Mary's) - Good between southwest, west, northwest, north, and light northeasterly.

  • Watermill Cove Click to view haven (St Mary's) - Good between south, south-westerly or westerly.

  • St Helen's Pool Click to view haven (St Helen's Island) - Good in all weather conditions save for some swell at high water.

  • Green Bay Click to view haven (Bryher) - Good in most all conditions for those that can take to the bottom.

  • New Grimsby Click to view haven (between Tresco & Bryher) - Good in all weather except north-westerly.

  • The Cove Click to view haven (St Agnes) - Good between southwest, west, northwest, north, northeast and light southerly winds.

Those prepared to move should usually escape the worst of it save in during August when large numbers of French boats crowd the anchorages.


The Scilly's translucent waters greatly facilitate anchoring
Image: Michael Harpur

The bottom in much of the Scillies is deep weed or/and fine sandy patches. Those that properly anchor are unlikely to experience any problems – save from draggers who have not. A big advantage of the Scillies is that it’s the one place in England where the water is clear enough to see the bottom when anchoring.

St Mary's Boatmen's Association providing a comprehensive boating service
throughout the group from St Mary's.

Image: Visit Isles of Scilly

So even when weed is pervasive little pockets of fine sand usually can be seen among weed so that it is possible to drop the anchor straight onto sand and let it drag back to get a rock-firm grip on the edge of a weed bed. CQRs thrive in these environments where a Bruce, Admiralty pattern and Danforth have a tendency to choke in kelp before they set. The local recommendation is a wide-fluked Fisherman type which is an excellent gripper but may tear out if the ground's not hard enough. Generally, it is advisable to set a second anchor of a different type for total peace of mind, especially if the vessel is being left unattended for any time.

St Mary's Boatmen's Association ferry alongside Tean Sound Quay
Image: Michael Harpur

It is important to note that all the quays within the group are continuously being used by St Mary's Boatmen's Association who provide a comprehensive boating service throughout the group from St Mary's. Do not anchor or mooring in any fashion that can serve to obstruct their activities. Similarly, dinghies should never be left tied up to steps or near the heads of the working quays. Please land at the head of the quay if it is free and immediately pull the tender up onto the beach well clear of operations.


St Mary's Island
Image: Visit Isles of Scilly

Two miles long, from north to south, and 1¾ miles wide and rising to a 40 meters high summit in the north part, St Mary's Island is the largest island of the group. It is also the most populous island, home to 1,723 out of a total population for the Scilly Island group of 2,203 and its principal town of Hugh Town is the administrative centre, capital and the largest settlement on the Isles of Scilly.

St Mary's Harbour and Hugh Town
Image: Visit Isles of Scilly

The town is located on a narrow isthmus which joins the peninsula known as the Garrison, to the west, with the larger body of the island to the east. To the north of the isthmus is a natural bay of St Mary’s Pool Click to view haven. It is further protected to the west by the quay of Saint Mary's Harbour that also serves as a breakwater for the inner harbour area.

St Mary's Harbour
Image: Michael Harpur

Saint Mary's Harbour comprises a pier that extends northward to connect to Rat Island and a further 150 metres further northeastward where the island passenger ferry, The Scillonian III, has its berth. Close to its root is the Old Pier from which inter-island launches run by 'St Mary's Boatmen's Association' connect to all the other inhabited islands known as the off-islands. The harbour provides moorings and the possibility of coming alongside its wall. It is also possible to anchor outside the harbour limits.

Porth Cressa
Image: Michael Harpur

To the south of the isthmus is a natural bay Porth Cressa Click to view haven. Sometimes spelt Porthcressa, the bay is sheltered by The Garrison and Morning Point to the west, Carn Mahael and Peninnis Head to the east, and the isthmuses' long south-facing arc of beach at its head. Porthcressa Beach is probably the most popular beach on the island with visitors and locals alike using it for sunbathing, swimming and generally relaxing.

Old Town Bay
Image: Michael Harpur

Less than a mile to the southeast on the southern side of the island adjacent to Porth Cressa lies Old Town Bay Click to view haven that was the original medieval port of St Mary’s before it was superseded by Hugh Town. It is today a tiny village overlooking a drying bay with the old stone wall and a slip on its eastern side.

Watermill Cove
Image: Michael Harpur

Watermill Cove Click to view haven is a historic anchorage in a remote setting on the northwest coast of St Mary's Island, Isles of Scilly. It presents a beautiful sandy beach fronted by clear blue water at low water. It is a remote location well used by passing yachts as it provides both a good anchorage and a tide wait location laying adjacent to Crow Sound, that requires sufficient rise of the tide to pass over Crow Bar, that has about 0.7 metres LAT.


Tresco Island is the second-largest island of the Isles of Scilly. It is 2 miles long north and south, and ¾ of a mile wide and contains 297 hectares. The two principal settlements are New Grimsby and Old Grimsby in the central part of the island.

Tresco as seen from the east
Image: Tom Corser via CC ASA 2.0

New Grimsby Click to view haven lies in the north end of the channel between Bryher and Tresco about midway along the island's western coast. New Grimsby Sound's deep waters offer one of the best Scilly all-weather havens. There is a quay, as well as a public house and a small art gallery. The southern portion of the settlement, on the site of Abbey Farm, includes the Tresco Estate's Island Office, the island's convenience store with a post office sub-branch inside and a restaurant. On the opposite side of the sound is Bryher Village the principal settlement of the smallest populated island of the group.

New Grimsby
Image: Michael Harpur

The seaward entrance is at the north end of the island group but it also may be approached from the south from St Mary’s Road over Tresco Flats typically 2 hours either side of high water as detailed in the Tresco Channel crossing the Tresco Flats Route location route.

Old Grimsby
Image: Michael Harpur

Located on the east side of the island is Old Grimsby Click to view haven the other principal settlement. It is fronted by a harbour with a drying quay. The harbour is set into a bay that comprises Raven's Porth and Green Forth, that are separated by its central Quay and both dry to 2.3 and 2.2 metres respectively. The island's community centre and adjacent to it the primary school for Tresco and Bryher lie ashore. There is also a café, Ruin Beach, by the beach in the main part of the settlement. At the southern end of the bay is a 16th-century Blockhouse that has guarded the historic anchorage since Tudor times and beyond this are a string of wide white sand beaches.


St. Martin's Island, the north-easternmost populated island of the Isles of the Group. It has an area of 237 hectares and is about 2 miles long northwest/south-east, and ⅔ of a mile wide. To the north, St Martin's is joined by a tidal causeway to White Island. The most remarkable object is the beacon known as the daymark, which stands on the highest and eastern part of the island, at an elevation of 56 metres. It is a rendered granite circular tower 4.8 metres in diameter and 6.4 metres high, set back to conical termination making it 11 metres high, painted with alternate red and white horizontal bands.

St Martin's Island as seen from the southeast
Image: Tom Corser via CC ASA 2.0

There are three main areas of settlements on the island, Higher Town, Middle Town and Lower Town but in all these cases the term 'town' in their titles should not be taken as something that indicates large settlements. The north and northeastern side of Scilly is much less developed than the other inhabited isles and St Martin’s as a whole, including its scattering of farms and cottages, has a population of less than 150 people.

Higher Town Quay
Image: Michael Harpur

The modernised Higher Town Quay situated on its western end of Higher Town Bay Click to view haven, on the south side of the island at the head of an open bay that lies between Cruther’s Hill and English Island Point, is the principal landing point for cargo and passengers for the island. It is as often as not also known by its beach, Par Beach, that is one of St Martin’s outstanding features. Sat at the head of St Martin's Flats, the bay and quay dry out entirely to clean sands on low spring tides. This makes the domain of shoal draft vessels that can take to the bottom. It is nevertheless just about flat enough to use for vessels carrying beaching legs and moderate draft vessels can lie afloat during neaps.

Tean Sound at the west end of St Martins
Image: Visit Isles of Scilly

Because Higher Town Quay dries and has limited capacity, certain combinations of tidal and weather conditions result in the island's west end quay located at Lower Town, Tean Sound, often called Hotel Quay, being used for foot passengers if cargo operations remain concentrated at Higher Town. The adjacent Tean Sound Click to view haven has a number of moorings laid in the protected pool in front of Karma St Martin’s. Deep and picturesque it one of the best of the handful of anchorages that St Martin’s has to offer to deeper draught boats.

St Martin's Daymark tower overlooking Bread and Cheese Cove
Image: Scilly Aerial Photography

On the northeast corner of the island, there is a deepwater anchorage called Bread and Cheese Cove Click to view haven that has a small beach set into a beautiful north-facing bay. Remote and lying beneath Chapel Down, the high easternmost hump of St Martin’s, it is easily located by the large candy-striped daymark set on the summit of the down above it. The bay offers a well-protected deep water anchorage over a bottom comprised of sand, rock and weed.

Bull's Porth
Image: Michael Harpur

Adjacent and close west to Bread and Cheese Cove is the alternate Bull's Porth Click to view haven anchorage which is another north-facing bay between Turfy Hill on the west and the Burnt Hill promontory to the east. Visiting boats will most likely have these cove to themselves as this is very much off the beaten path in a remote what is a very undeveloped part of the island.

Secluded Perpitch
Image: Michael Harpur

On the south side of Chapel Down is a small sandy crescent tucked away on the eastern corner of St Martin's called Perpitch Click to view haven. Tucked in between Gun Hill and Brandy Point and flanked by moderately high ground and surrounded by flats and reefs, that break up the majority of any swell, it provides a reasonable anchorage and a wonderfully protected breach. It is however shallow, 1.2 metres LAT, with a stony ledge of 0.5 metres just before the anchoring area which makes it more suitable for shoal draft vessels.


Bryher lies to the west of Tresco and is one of the smaller of the inhabited islands of the group. It is 1½ miles long from north to south, ⅔ of a mile wide, and attains an elevation of 39 metres and contains 134 hectares. Off the southern end of Bryher is the uninhabited island of Samson. It is marginally the smallest island in area and population when the tidal island of Gugh is included with St Agnes which is the common interpretation. It is possible to walk around the island in little over an hour and between Samson, Tresco and Bryher at the lowest spring tides.

Bryher lying westward of Tresco
Image: Michael Day via CC BY-NC 2.0

The small island composed of a series of five small rounded granite hills that range in height from between 33 and 42 metres with a mainly low-lying with arable fields, pasture and housing. Most of the houses are near its twin Quays in, the outsized named, Bryhertown that describes the 20 or so houses overlooking the New Grimsby Sound Click to view haven between it and Tresco. The bay immediately south has the island's two principal quays used by the island ferries. The Quay, also known as Church Quay which dries to 2.4 metres at the southern end and Anneka's Quay, also known as The Bar, at the north end that also dries to 1.1 metres and is used at low water.

Green Bay Bryher
Image: Michael Harpur

The drying bay immediately south, Green Bay Click to view haven facing Tresco across the shallow waters of the Tresco Channel is a perennial favourite for vessels that can take to the bottom. It is a wide expanse of fine sand backed by trees and shrubs with a small boatyard at its southern end that offers facilities. It offers the best all-round protection of any Scilly harbour for those that can take to the bottom or have beaching legs.


St Agnes Island is the southernmost populated island of the group and separated from St Mary's by St Mary's Sound. The island is 1 mile long, and ¾ of a mile wide it contains 148 hectares, including Gugh Islet, with which the island is connected by a narrow tombolo called The Bar, locally known as Gugh Bar, that covers at three-quarter flood.

Porth Conger St Agnes' principal quay with Gugh in the backdrop
Image: Michael Harpur

The two islands of St Agnes and Gugh together have a population of 85 residents (2011 census). Troy Town Farm on the island is the southernmost settlement in the United Kingdom and England. St Agnes is the only populated island in the group which has no hotel. However, it has an ice cream shop, a campsite, a small post office and general store and a gift shop. It also has a pub (the Turk's Head) and a café that are open during the season.

The Cove on the south side of The Bar
Image: Michael Harpur

The island offers two berths, The Cove Click to view haven that lies to the south of The Bar and Porth Conger Click to view haven opposite, which has the island's principal quay, on the opposite northern side. The Cove is the larger and the deeper of the two bays with 7 metres or more in the middle and ample room for 20 boats to anchor with excellent sand holding.

The island's most notable landmark is its disused lighthouse that stands on the summit of the island. It has been converted into living accommodation and the tower no longer contains a light. A rock formation on the southwest side of St Agnes that looks like an elephant.


St Helen's Island with yachts anchored in St Helen's Pool
Image: Michael Harpur

St Helen's is is the third largest of the uninhabited islands in the Scilly archipelago. Comprising a total area of 20 hectares it is made up of a smooth 42 metre high rounded hill that is covered in grass and heather. We mention this island because of St Helen's Pool the spacious stretch of water lying close south of the island which provided a well-used anchorage for sailing ships in the past. St Helen's Pool Click to view haven remains an excellent deep water leisure boat anchorage today with a unique property for the island group of enjoying near all-round protection.


The complete course is 25.12 miles from the waypoint 'Gwennap Head, the southwest extremity of the Cornwall Peninsula' to 'Saint Mary's Sound, Isles of Scillies ' tending in a west south westerly direction (reciprocal east north easterly).

Gwennap Head, the southwest extremity of the Cornwall Peninsula, 50° 0.686' N, 005° 40.270' W
This is ½ south of the lit 'Runnel Stone' south cardinal, Q(6)+ LFl.15s. The marker buoy marks the drying Runnel Stone that lies ¾ of a mile south from Gwennap Head. The buoy is moored 350 metres to the south of the danger.

       Next waypoint: 25.12 miles, course 253.27°T (reciprocal 73.27°T)

Saint Mary's Sound, Isles of Scillies , 49° 53.357' N, 006° 17.590' W
This is southeast of the entrance to Saint Mary's Sound the safest and easiest approach to the island group. It is on the 307° T alignment of the western extremity of Great Minalto with North Cam of Mincarlo that leads through Saint Mary's Sound and 1 mile out from the lit ‘Spanish Ledge’ East Cardinal Mark, Q(3)10s.

What is the best sailing time?
May to September is the traditional UK Sailing season with June-July offering the best weather. The British Isles weather is highly variable, and the amount of bad weather varies quite widely from year to year. This is because they are islands positioned between the Atlantic Ocean and the large landmass of continental Europe. As a result, the entire area lays under an area where five main air masses meet and alternate:

  • • Tropical Maritime Air Mass - from the Atlantic

  • • Polar Maritime Air Mass - from Greenland

  • • Arctic Maritime Air Mass

  • • Polar Continental Air Mass - from central Europe

  • • Tropical Continental Air Mass - from North Africa

Depending on the movements of the jet stream, any and all of these air masses can come in over the isles, creating weather fronts where they meet and bringing with them all types of weather.

The prevailing winds for the British Isles as a whole are from the western quarter which generally blows for two-thirds of the year predominantly from the southwest. Gales from the westward are felt in all seasons, but from November to March, inclusive, they are most frequent and generally last three or four days. Of these, a southwest gale is considered to be the most powerful system. The winter period is largely characterised by wind and rain.

The fine summer weather of the sailing season is typically punctuated by the passage of an Atlantic depression that bringing periods of strong wind and rain, and sometimes poor visibility. These gales rarely cause surprises as they are usually forecasted well in advance. Good weather windows of 48 hours are easy to predict but any longer than that there's an increasing chance of change.

Fogs are frequent in all parts of the Channel and are formed both on the English and French coasts. In summer they only obscure the land in the morning and are readily dispersed by heat or a light breeze. But the moist haze, driven in by westerly winds from the sea, tends to linger and is only dispersed by strong winds. In the eastern part of the Channel, it is rare for the land to be completely free from mists. The only exception is when the wind is from the northeast which makes the mist free coastline highly distinctive from a great distance.

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