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Dalkey Sound

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Dalkey Island lies off the southern point of the entrance to Dublin Bay, about two and a half miles southeast of Dún Laoghaire Harbour on the east coast of Ireland. The anchorage is in Dalkey Sound off the northwest corner of the uninhabited and interesting Dalkey Island.

Although providing good protection from westerly and easterly conditions, and having the benefit of good holding, this can only be classed as an exposed anchorage owing to the sound’s strong currents and funnelling winds. It is best avoided in any brisk conditions from the northwest through northeast, and southwest through southeast, particularly so in wind-over-tide conditions that make it particularly uncomfortable. Daylight approaches are straightforward as the sound’s fairway is deep and clear following an approach off the mainland’s steep-to shoreline.
Please note

Because of the strong tides and funnelling winds it is not a place to leave a boat unattended for any period. If landing a shore party to visit the island it would be best to leave a competent crew member on board.

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Keyfacts for Dalkey Sound
Slipway availableMarked or notable walks in the vicinity of this location

No fees for anchoring or berthing in this locationRemote or quiet secluded locationAnchoring locationJetty or a structure to assist landingQuick and easy access from open waterHistoric, geographic or culturally significant location; or in the immediate vicinity

Note: strong tides or currents in the area that require consideration

Protected sectors

Current wind over the protected quadrants
Minimum depth
2 metres (6.56 feet).

4 stars: Straightforward; when unaffected by weather from difficult quadrants or tidal consideration, no overly complex dangers.
2 stars: Exposed; unattended vessels should be watched from the shore and a comfortable overnight stay is unlikely.

Last modified
April 28th 2020


An exposed location with straightforward access.

Slipway availableMarked or notable walks in the vicinity of this location

No fees for anchoring or berthing in this locationRemote or quiet secluded locationAnchoring locationJetty or a structure to assist landingQuick and easy access from open waterHistoric, geographic or culturally significant location; or in the immediate vicinity

Note: strong tides or currents in the area that require consideration

Position and approaches
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Haven position

53° 16.380' N, 006° 5.280' W

In the anchorage area.

What are the initial fixes?

The following waypoints will set up a final approach:

(i) Dalkey Sound south approach initial fix

53° 16.140' N, 006° 5.240' W

This waypoint is in the channel 400 metres south of anchorage.

(ii) Dalkey Sound north approach initial fix

53° 16.750' N, 006° 5.730' W

This waypoint is in the channel half a mile northwest of the anchorage.
Please note

Initial fixes only set up their listed targets. Do not plan to sail directly between initial fixes as a routing sequence.

What are the key points of the approach?

Offshore details are available in eastern Ireland’s Coastal Overview for Dublin Bay to Rosslare Harbour Route location. A useful set of waypoints and approach descriptions are available in the routes entry ‘Dublin to Killiney Bay via Dalkey Sound’ Route location.

Not what you need?
Click the 'Next' and 'Previous' buttons to progress through neighbouring havens in a coastal 'clockwise' or 'anti-clockwise' sequence. Below are the ten nearest havens to Dalkey Sound for your convenience.
Ten nearest havens by straight line charted distance and bearing:
  1. Sorrento Point - 0.2 miles SW
  2. Dún Laoghaire Harbour - 1.5 miles NW
  3. Bray Harbour - 2.4 miles S
  4. Dublin Port (Poolbeg Marina) - 3.9 miles NW
  5. Balscadden Bay - 4.3 miles N
  6. Howth - 4.5 miles N
  7. Greystones - 4.5 miles S
  8. Carrigeen Bay - 4.9 miles N
  9. Malahide - 6.9 miles NNW
  10. Talbot’s Bay - 8 miles N
These havens are ordered by straight line charted distance and bearing, and can be reordered by compass direction or coastal sequence:
  1. Sorrento Point - 0.2 miles SW
  2. Dún Laoghaire Harbour - 1.5 miles NW
  3. Bray Harbour - 2.4 miles S
  4. Dublin Port (Poolbeg Marina) - 3.9 miles NW
  5. Balscadden Bay - 4.3 miles N
  6. Howth - 4.5 miles N
  7. Greystones - 4.5 miles S
  8. Carrigeen Bay - 4.9 miles N
  9. Malahide - 6.9 miles NNW
  10. Talbot’s Bay - 8 miles N
To find locations with the specific attributes you need try:

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Please use our integrated Navionics chart to appraise the haven and its approaches. Navionics charts feature in premier plotters from B&G, Raymarine, Magellan and are also available on tablets. Open the chart in a larger viewing area by clicking the expand to 'new tab' or the 'full screen' option.

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How to get in?

Dalkey Island is situated off the south point of the entrance to Dublin Bay about 500 metres east of the mainland’s Sorrento Point. It is 24 metres high and 600 metres long, northeast to southeast, with a Martello tower on its summit. The anchorage is on the northeast side of the island within Dalkey Sound through which it is approached. The sound lies between the island and the mainland providing a clear passage, with from 6.8 to 12.6 metres of water in the fairway, and is about 230 metres wide in total.

Tides funnel through the Sound and are a prime consideration for those approaching this anchorage. Streams attaining speeds of up to 1.5 to 2.5 knots and there are often overfalls caused by the reconnection of tide runs that wrap around the island just off Sorrento Point.

Northern Approach Vessels approaching from the north and Dublin Bay will clearly see the 24 metres high Dalkey Island from across the bay. About 600 metres to the northeast of Dalkey Island there is a smaller 6 metres high rock islet called the Muglins. The Muglins is a different rock group that are not connected to Dalkey Island. A lighthouse on the 6 metres high Muglins, more aptly described as a distinctive beacon, makes it highly recognisable. It is a white conical tower with a red band standing 9 metres Fl 5s range of 11M.

Muglins – Lighthouse Fl R 5s position: 53° 16.524'N, 006° 4.579'W

Dalkey Island has foul ground with drying rocks and shoals that extend up to half a mile north by northwest of the island. The leading rock is Maiden Rock, or Carraig Rock, that stands 11M high and is always visible. After this, there are several rocks such as Clare Rock and Lamb Island, due east of Coliemore Harbour on the mainland, that are all part of a large ridge extending north-westward from Dalkey Island, of which some are visible at low tide.

Favouring the mainland’s steep-to shoreline side of Dalkey Sound avoids all issues as the dangers are all on the Dalkey Island side. The shore between Bullock and Dalkey is clear of danger and steep-to and no dangers are likely to be encountered passing 100 metres off the shoreline.

On closer approaches in the anchoring area, to the north of the landing area where steps can be seen on the island, there is another reef. This has 0.6 metres over it and it runs out 70 metres from the shore.

Southern Approach Vessels approaching from the south will find Killiney Bay to be composed of a shingly beach that is foul along the shoreline. It is best to keep half a mile off where there will be in excess of 10 metres of water. The Frazer Bank is situated to the southeast of Dalkey Island. With a least depth of 5.3 metres, it presents little issue for a leisure craft.

Align a central path of approach favouring the steep-to mainland side keeping about 100 metres off. However, the tides wrap around the Killiney Bay and may be felt abeam on approach to Sorrento Point. Also in this location look out for overfalls caused by the reconnection of tide runs that wrap around the island.

Keep well off the island as Dalkey Island’s southwest corner is foul. From beneath the southern fort a reef extends 50 metres along the island’s western shoreline to about halfway along the coastline area that leads to the Martello Tower. There is a further rock, scarcely awash at low water, close to the south of the landing steps near the ruin of the old church.

Haven location Anchor in 5 metres to the north of the midpoint of the island. The seabed is rocky with indifferent holding. It also shelves steeply, so that anchoring too far out places a vessel in deep water, whilst anchoring in shallow water places the vessel uncomfortably close to the island.

Land at the slipway on the northwest corner where, as of 2014, newly improved steps can be seen leading up to the island. Haul the dinghy out as the currents run strong here, but do not block the slip as it is used by local pleasure craft from Coliemore.

Alternatively, there is a little cove just alongside the slipway and the beach, to the west of ruin of the little Church of St. Begnet. This landing point may be used for the top two-thirds of the tide.
Please note

If wind and tide make the anchorage uncomfortable, an alternative can be found under Sorrento Point just a few hundred metres south.

Why visit here?
Dalkey Island derives its name from the Danes who had a fortress and trading post here in the 10th-century. The original name 'Deilginis' was the conjunction of the Irish words deilg, meaning thorn, and inis meaning island, creating a name that basically means 'thorny island' but one that was heard as 'dagger island' or 'cloak-pin island'. The Danes simply borrowed deilg into their dálker and translated the inis into the Old Norse 'øy' or 'ey', meaning 'island' transforming the name into the present Dalk – ey.

As its Viking name suggests the small island is steeped in history with evidence of inhabitation that goes back 6,000 years to the 4th millennium BC. Excavated artefacts presenting evidence of the island’s Mesolithic, or Middle Stone Age, occupation are housed in the National Museum in Dublin. They include Mesolithic Bann flakes, Neolithic hollow scrapers and Bronze Age arrowheads. Settlers continued to use the site throughout the Iron Age as is demonstrated by the promontory fort located at the northern end of the island. Worn by time, the fort is just perceptible today in the form of a ditch, which will be readily identified by those who know what they are looking for.

The island’s Early Christian period is well witnessed by the remains of the 9th or 10th Century St. Begnet stone church. An older wooden church was probably here before the present stone building and the existing ruin has been modified throughout the ages. The doorway lintel is typical of the period prior to the twelfth century and the church’s bellcote, high on the gable, is most likely to have been a 15th-century addition. The church takes its name from the patron saint of Dalkey. Noted as a "virgin, not a martyr", St. Begnet’s feast day is November 12. A Holy Well, situated near the Martello tower, is also associated with her and it is said to provide a cure for rheumatism.

The church was most likely abandoned when the Vikings used the island as a base and coined its name. During this time the island would have been one of the busiest ports in Ireland. This base for sea-going traders continued into the early medieval period when the island was a hub for the importation of goods from western France and the Mediterranean. In the Middle Ages, Dublin’s main port was Coliemore Harbour immediately opposite the island. Eventually, large ships could not navigate the shallow and silting Liffey whereas the Dalkey Sound provided deep water and a tidal conveyor belt to slip a berth. Goods were then transported to the town by a causeway across Dalkey Common which most likely took the path of the current Coliemore road location.

The most visible of the island’s legacy dates back to the 19th century and the defence constructions of the British Admiralty. Centremost amongst this is the island’s dominating and exceptionally large Martello Tower that was built on the island’s summit in 1804. During this period the little church served as living quarters for the builders of the tower and gun battery when the fireplace on the east side was added.

The Dalkey Martello is one of three ‘double towers’ built in Dublin to take two 18 pounder cannons on a roof platform - they were soon upgraded to 24 pounders. The Dalkey Island Martello originally was a totally unique design, as it is the only Martello tower known anywhere in the world to have been built without a doorway. Because the doorways of Martello towers were a vulnerable point and ships could sail entirely around Dalkey Island, the tower on the island was accessed via a ladder that was secured to the roof. A large hatch was inserted through the ‘bombproof’ granite roof to allow stores to be hauled up and then lowered into the tower. The present entrance was a later insertion that leads directly into the magazine.

The guns on the tower were intended to work in tandem with the gun battery set into the island’s southern granite cliffs. Constructed at the same time it housed three 24 pounders and was expanded and altered over time. Both combined to command the approaches to Dublin Bay and the anchorage of Dalkey Sound and they made Dalkey Island the most heavily armed position in the chain of coastal fortifications. These included seven other towers dotted along Dublin’s coastline to provide the capital with an early warning and defence system against the threat of a Napoleonic invasion that never came in the end.

Military personnel were removed from Dalkey Island in 1886, it was one of the last of the Dublin towers to be disarmed. Today, the Martello tower remains in local authority ownership and is currently locked up with no public access. Sometimes the lock on the door is broken and the tower accessed. The abandoned tower looks very similar to how it must have appeared when first completed but the battery gradually fell into ruin.

The small island is uninhabited today but there is plenty of wildlife here. It is host to a herd of goats that were originally brought here in the early 19th century. The current ones, however, are replacements of the original goats that were removed. Plenty of rabbits also live on the island. Offshore a colony of seals, which has greatly expanded in recent years, live around the rocky shores of the island. More recently a pod of three bottlenose dolphins have begun frequenting the waters around Dalkey Island.

Dalkey Island may offer the coastal cruiser an exposed anchorage but it is a location where it is well worth getting the dingy out. The island provides a magnificent walk through a scarcely trampled piece of national history. The views out over Dublin Bay, Killiney Bay and the Wicklow Mountains from both the Martello Tower and the ruined forts are simply spectacular.

What facilities are available?
Apart from the slip there are no facilities on this uninhabited island.

Any security concerns?
Never an issue known to have occurred at Dalkey Island.

With thanks to:
Charlie Kavanagh, ISA/RYA Yachtmaster Instructor/Examiner.

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Please zoom out to see the 'initial fixes' for this location.
The above plots are not precise and indicative only.

A photo montage of the island area

A RIB approaching the island from Dún Laoghaire Harbour.

A view from the island

A tour of island

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