Clew Bay
53°48.4'N 009°40.0'W · Westport Quay (County Mayo) (8nm)
3–7m
Depth
Good
Holding
85m
Alarm radius
Low
Crowd level
Clew Bay is one of the most beautiful anchorages on Ireland's Atlantic coast — a vast, island-studded bay at the foot of Croagh Patrick (762m, Ireland's holy mountain) in County Mayo. The bay contains approximately 365 drumlins (glacially-formed islands) creating a complex labyrinth of channels and anchorages that provide outstanding Atlantic shelter. Westport (8nm) is a charming Georgian planned town with excellent provisions and restaurants. The Pirate Queen Grace O'Malley (Granuaile) ruled these seas from Rockfleet Castle at the inner bay head in the 16th century — her tower still stands. Croagh Patrick's pyramidal silhouette behind the bay creates one of the most dramatic landscapes in Irish sailing.
Best Months
Anchor Zones
Old Head — main anchorage in inner bay
Good3–7m · Alarm: 85m
Anchor in 3–6m (CD) off Old Head in the inner part of Clew Bay, using the numerous islands as a windbreak. Sand and mud — good holding once the anchor is set. Clew Bay contains approximately 365 islands (one for every day of the year according to local legend) — the inner bay is well sheltered by these islands from Atlantic swell except in extreme westerly conditions. Tidal range approximately 3.5–4.5m springs. Navigation through the islands requires careful chart work — consult ICC Sailing Directions.
Setting Your Anchor Alarm
85m radius for the inner bay anchorage. The complex island topography creates local wind effects — gusts can be channelled between islands. Tidal range of 4.5m springs means actual depths at HW are 7.5–11.5m; plan scope accordingly. In sustained westerlies with the bay open to the W/NW, the anchorage off Old Head can be exposed — move to a more sheltered island anchorage on the N side of the bay.
Recommended radius: 85m
Hazards & Warnings
- !Complex navigation among 365 islands — large-scale chart and ICC Sailing Directions essential; GPS alone is insufficient for safe island navigation
- !Extensive oyster and mussel farm infrastructure throughout the bay — marked on charts but can be difficult to see, especially in low light
- !Atlantic swell from the W/NW affects outer parts of the bay — the inner bay provides better shelter but assess conditions carefully
- !Tidal range 3.5–4.5m springs — extensive drying areas between islands; calculate actual depths carefully
- !Croagh Patrick pilgrim season (last Sunday of July — Reek Sunday) brings enormous crowds to the local area — not directly affecting anchorage but worth noting
Skipper's Tips
- ✓ICC Sailing Directions for West Ireland (available from irishcruisingclub.com) are essential for safe navigation in Clew Bay — buy and study before departure
- ✓Westport is one of Ireland's most welcoming towns — excellent pubs (Matt Molloy's pub, owned by the Chieftains flute player), good restaurants and food market
- ✓Croagh Patrick can be climbed from Murrisk (3nm from Westport) — allow 3–4 hours return; outstanding views over the bay on a clear day
- ✓Clare Island at the bay entrance offers a welcoming harbour and accommodation — a good staging post
- ✓Rockfleet Castle (Grace O'Malley's stronghold) is accessible at HW by dinghy — a remarkable piece of Irish history
Facilities
Anchoring Rules
- Permit:
- Not required
- Fee:
- Free
- Restrictions:
- Many of the smaller channels between islands have drying patches — navigate only with large-scale chart and ICC Sailing Directions (W Ireland vol.). Check for oyster and mussel farms (numerous in Clew Bay) — avoid anchoring on farm infrastructure. Respect private island properties.
Sleep Safely at Clew Bay
Set your anchor alarm to 85m. UK tidal ranges mean your boat swings — Safe Anchor Alarm keeps watch through the night.
Download Safe Anchor Alarm — Free