Dun Laoghaire is situated on the south of Dublin Bay, 12km from the city centre. It is a major ferryport and with four Yacht clubs and a 500 berth marina, it is also the major yachting centre on the east coast. The main depot and workshops of the commissioners of Irish Lights are situated in the harbour and there is also a RNLI station providing both inshore and offshore services. The Harbour has three main berths off the number 1 fairway with the east pier berth (No 1) used chiefly by Naval and Commissioners of Irish lights vessels.

Carlisle Pier (No 2 & 3) is no longer in operation and awaiting redevelopment. A major redevelopment at St Michael's Pier (No 5) was complemented in October 1995 ready to accept the World's first Highspeed Sea Service (HSS) which commenced in 1996. The HSS services the Holyhead, North Wales- Dun Laoghaire route of Stena Line.

In 2003, Dun Laoghaire handled 967,318 passengers, 193,482 vehicles and 34,745 ro-ro units from 1,074 HSS entries. Local fishing boats use Traders Wharf and there are over 500 swinging moorings for the four yacht clubs.

The 600 berth Marina, which is encompassed by two new breakwaters within the harbour, officially opened in 2001.

Port details:

The East Pier at 1,290m and West Pier at 1,548m form and enclose the harbour and its piers. The main No 1 Fairway is dredged generally to 5.8m CD. There is a dedicated HSS linkspan on No 5 berth.

The Number 4 berth ramp is built to BS, and is 3.0 m wide and have a max slope of 1:8 with linkspans designed to operate shore to ship's ramp. Vessels of 17.37m beam and up to 134m in length can use No 4 berth.

Services: