Portmuck Harbour offers a diverse marine environment featuring a sheltered sandy bay and a steep bedrock wall on the seaward side. This site comprises reef, wall, and artificial reef structures, suitable for intermediate divers. Depths range from 1m to 15m, with an average of 5m. Shore access is available, though divers should be aware of moderate currents, surf, and potential rip currents. Visibility fluctuates between 5m and 20m. Water temperatures are cool, ranging from 8C to 14C, necessitating the use of drysuits or heavy wetsuits. Facilities at the site include parking, toilets, showers, and a rinse station. Typical dives last approximately 45 minutes.

Skernaghan Point in Strangford Lough offers a drift diving experience across a varied seabed of sand, gravel, and extensive brittlestar beds. This site is suitable for advanced divers, with depths ranging from 3 to 30 metres. Conditions are variable, with visibility typically between 3 and 20 metres and moderate currents. Divers and snorkellers can access the site from both shore and boat. Water temperatures fluctuate between 8C and 14C throughout the year. Hazards at this location include potential entanglement and strong currents. Facilities available at the site include parking and toilets.

Isle of Muck in Strangford Lough offers a challenging dive featuring a vertical bedrock wall with deep crevices. Located off the northern tip of the island, this site is suitable for advanced divers due to the moderate currents and depth, which starts at 16 metres. Access is strictly by boat. The site is also rated for snorkelling. Water temperatures fluctuate between 8C and 14C throughout the year. Divers should be aware of hazards including boat traffic, significant depth, and strong currents. Shore-based facilities near the departure point include toilets, showers, and a cafe, with guided tours available.

Ferris Bay is a quiet, northwest-facing sandy bay located near the entrance to Larne Lough in Strangford Lough. This site offers a peaceful environment for shallow water exploration and is suitable for beginners. Access is via the shore. Water temperatures in this marine environment vary throughout the year, ranging from 8C in March to 14C between August and October. As a snorkel site, it provides a calm alternative to nearby locations, though conditions can vary. There is no specific data regarding marine life at this location.

The Gobbins is a marine site situated at the base of dramatic basalt cliffs in Strangford Lough. This location features a combination of caves and drop-offs, providing a unique perspective of the cliff-base topography. Access is strictly by boat, and the site is suited for advanced snorkelers due to the presence of moderate currents, surge, and surf. Water temperatures range from 8C to 14C throughout the year. Divers and snorkelers should remain vigilant regarding boat traffic, cold water conditions, and the presence of jellyfish. Facilities including parking, toilets, a cafe, and equipment rental are available nearby.

Waterloo Bay in Strangford Lough offers a shallow snorkeling experience over ancient mudstone ledges. The site is notable for its Jurassic fossils and geological history along the Antrim coast. With depths ranging from 1 to 10 metres and an average of 5 metres, it is suitable for beginners entering from the shore. Conditions include moderate currents and potential surf. Species recorded around this area include snails, brittle stars, rock crabs, European green crabs, shannies, sea squirts, and catsharks. Facilities at the site include parking, toilets, and a cafe, with guided tours available for those interested in the local geology and marine environment.

Blackhead Caves, located at the southern base of Islandmagee, offer a shallow dive experience consisting of rocky reefs and sea caves. The site is suitable for intermediate divers, with depths ranging from 1 to 10 metres and an average depth of 5 metres. Access is via a shore entry. Divers should be prepared for moderate currents and surge, as well as potential hazards including entanglement, low visibility, and the overhead environment of the caves. Visibility at the site varies between 5 and 20 metres. Water temperatures fluctuate between 8C and 14C throughout the year. Parking is available for visitors.

Drains Bay is a shingle beach located north of Larne in Strangford Lough. This site features rocky outcrops at both ends of the beach, providing a shallow environment suitable for beginner snorkellers. Access is via the shore, and the site offers facilities including parking and toilets. Conditions are generally mild, though water temperatures fluctuate between 8C and 14C throughout the year. As a shore-based location, it provides a relaxed setting for those looking to explore the coastal topography of the area.