Route summary
Distance: approximately 8 nautical miles
Time: 3–4 hours
Start and finish: Trearddur or Porth Dafarch
Best conditions: a calm summer day on an ebbing neap tide
This route follows a varied coastline with sea arches, blowholes and caves rich in wildlife. Large swell, or moderate or strong wind from NW through S, makes this stretch dangerous.
Tidal and launch information
Tides around Rhoscolyn are complicated by eddies and opposing channels and vary considerably from neaps to springs. Launch one to two hours after high water at the Trearddur slipway. Keep closer to the south side of the bay, then follow the coastline past Porth Diana and Raven’s Point.
HWS/LWS offshore is approximately Liverpool high or low water minus 1:30. In the Sound it is approximately minus 3:00. Tidal streams around Rhoscolyn Head and the islands should be respected, especially on springs.
Hazards and weather
Prevailing south-westerly winds can cause clapotis and confused seas. Winds and swell between south and northwest can create confused conditions. Offshore easterlies may be calmer but can produce sudden downdrafts and gusts. There are overfalls near Maen y Fran on the ebb, rocky coastline with limited landing options, and strong tidal flow around Rhoscolyn Point.
Route description
Pass the sea arches Bwa Du and Bwa Gwyn with care: they dry as the tide falls and should not be approached in swell. Continue around Rhoscolyn Head, keeping clear of the islands and shallow channels, then cross the Sound back towards Borth Wen. The old lifeboat station and slipway provide a useful landmark. Return along the coastline, watching for rocks by the arches and allowing the tide and weather to determine the safest line.
HM Coastguard, Holyhead: 01407 762051 / 763911
Adapted from a kayak route description by John Willacy, with additional information from Glazebrook’s North Wales Pilot.