

Best for beginner divers, 12m, boat entry, moderate current.
The Chasms is a reef and drift dive site located off the coast of Pembrokeshire. Divers typically explore the reef at a consistent depth of 12 metres, though the seabed drops to 27 metres, requiring careful depth monitoring. Access is by boat only, and the site experiences moderate currents, making slack water timing essential for a safe dive. Visibility at this location ranges from 3 to 6 metres. Due to active boat traffic at the surface, the use of a surface marker buoy is strongly recommended for all ascents. Water temperatures fluctuate between 9 and 16 degrees Celsius, necessitating appropriate thermal protection such as a drysuit or thick wetsuit.
53.41250, -4.68888
Time your dive around slack water to manage the moderate current, as drift conditions can catch inexperienced divers off guard. A surface marker buoy is strongly recommended for every ascent given the boat traffic in the area.
Access is by boat.
Recorded at this site
Depth
12m
Visibility
3-6m
Skill Level
Beginner
Entry
Boat
Boat required
Water Temp
9-16°C
Current
Moderate
The reef is situated at a consistent depth of 12 metres, with the seabed reaching 27 metres.
While the entry requirement is an Open Water certification, the moderate currents and boat traffic mean divers should be comfortable managing water movement.
This is a boat-only dive site located approximately 16 kilometres from the shore.
The main hazards include moderate currents and active boat traffic at the surface.
This site is designated for diving and requires boat access, making it unsuitable for snorkelling.
Diving at The Chasms in Holyhead requires the following certifications: Open Water. Always dive within your training limits.
Yes, equipment rental is available at or near The Chasms in Holyhead. Contact local dive operators for specific gear availability and prices.
A drysuit recommended is recommended for diving at The Chasms in Holyhead. Water temperatures range from 9°C to 16°C.
Expect moderate currents at The Chasms in Holyhead. Good buoyancy control and some drift diving experience is helpful.
Visibility at The Chasms in Holyhead typically ranges from 3 metres to 6 metres. Conditions vary with weather, tides, and seasons.