Porth Castell is a reef site in Pembrokeshire, United Kingdom, offering shore access for both divers and snorkellers. The topography features dramatic rock formations, a small island, and deep gullies. Depths range from 1 to 12 metres, with an average of 5 metres. Divers and snorkellers may encounter snails, which are very common, alongside uncommon species including wrasses, compass jellyfish, barrel jellyfish, tube worms, common moon jellyfish, sea squirts, shannies, clingfish, European green crabs, and rockpool prawns. Conditions vary, with visibility between 3 and 20 metres and mild currents. Hazards include boat traffic, rip currents, strong currents, and surf. Facilities available include parking, toilets, showers, a cafe, and a dive shop.

Craig-y-Mor in Pembrokeshire offers a rugged marine environment defined by underwater gorges and kelp-covered walls. Snorkellers should plan their visit around high tide to safely navigate the inner gullies. Water temperatures fluctuate between 9C and 16C throughout the year. Marine life recorded at the site includes common snails, alongside less frequent sightings of wrasses, brittle stars, sea stars, tube worms, and various crab species such as rock crabs and European green crabs. Jellyfish, including compass, barrel, and common moon varieties, are occasionally present. Due to the nature of the terrain and tidal requirements, this site is best suited for intermediate snorkellers.

Porth Dafarch in Pembrokeshire is a Blue Flag beach on Holy Island providing a shallow shore entry suitable for beginners. The site features a mix of rocky reef, kelp forests, and artificial structures. Divers and snorkellers can explore depths ranging from 2 to 8 metres, with an average depth of 6 metres. Visibility varies between 5 and 20 metres, and currents are generally moderate. Facilities at the site include parking, toilets, and showers. Due to its accessible nature and consistent conditions, it is a popular location for training. Divers should remain aware of potential boat traffic in the area.

Rhoscolyn at Borth Wen is a coastal site featuring a mix of reef and seagrass habitats. Divers and snorkellers can access the water directly from the beach or the boat slip. The topography includes a rocky shoreline with gullies extending toward a small island. Depths at this site range from 1 to 8 metres, with an average depth of 4 metres. Conditions are generally mild, though water temperatures fluctuate between 9C and 16C throughout the year. The site is suitable for beginners, though users should remain aware of boat traffic and the cold water. Facilities available at the location include parking, toilets, and showers.

Newry Beach in Pembrokeshire offers a shore-entry dive featuring a transition from sandy shallows to rocky reef and kelp forest environments. Divers typically explore depths between 3 and 10 metres, with an average depth of 6 metres. Conditions are generally mild, with visibility ranging from 5 to 15 metres. The site is suitable for beginners and supports night diving. Species recorded around this area include gray seals, catsharks, common lobsters, various crabs, and jellyfish. Facilities at the site include parking, toilets, showers, changing rooms, and access to air fills and guided tours.

The Flint Wreck is an accessible wreck site located in Pembrokeshire, United Kingdom, resting at an average depth of 9 metres. With a depth range of 8 to 10 metres, it is suitable for beginner divers and snorkellers. The site allows for both shore and boat entries. Visibility typically ranges between 5 and 10 metres. Divers should be aware of moderate currents and the presence of sharp edges on the wreck structure and surrounding rocks. Thick gloves are recommended for protection. Water temperatures fluctuate between 9C and 16C throughout the year, necessitating appropriate thermal protection such as a drysuit or thick wetsuit.

North Stack is a boat-access site located off the north-west tip of Anglesey, Pembrokeshire. The topography consists of a mix of reef, wreck, and drop-off features at depths between 10 and 20 metres. Divers should expect strong currents and limited visibility of approximately 5 metres, requiring careful navigation. Due to the challenging conditions, including boat traffic and surf, this site is suitable for intermediate divers. Water temperatures fluctuate between 9 and 16 degrees Celsius throughout the year, necessitating appropriate thermal protection. Divers must cross-reference tide tables with local skipper knowledge to time dives correctly and should deploy a delayed surface marker buoy during ascent.

The Missouri is a wreck site resting at a consistent depth of 14 metres, offering a practical experience for beginner divers. Accessible via both shore and boat entries, the site features mild currents and visibility typically around 5 metres. Divers should remain aware of the wreck structure and potential entanglement hazards from discarded fishing nets. Due to the limited visibility, a torch is recommended for exploring the wreck. Surface conditions require caution regarding boat traffic, and the use of a surface marker buoy is advised during ascent. Facilities including parking and toilets are available at the site. Water temperatures fluctuate between 9C and 16C throughout the year.