An Dun in Scapa Flow offers a varied environment for snorkellers. The site features a sheltered lagoon accessible at low tide, which is suitable for less experienced visitors. The outer reef area is intended for advanced snorkellers, characterised by dramatic kelp forests and deep gullies. These gullies contain a variety of invertebrates. Water temperatures at this site range from 8C to 14C throughout the year. Access to the water is via the shore.

The Void is a coastal reef site in Scapa Flow, Scotland, defined by a distinct shelf that drops into deeper water. Snorkellers can observe the transition from shallow kelp beds into darker, deeper areas. Access is via the shore, and the site is suited for intermediate snorkellers. Conditions include moderate currents and potential hazards such as boat traffic, entanglement, and low visibility. Water temperatures are cold, ranging from 8C to 14C throughout the year, necessitating appropriate thermal protection. Facilities at the site include parking, toilets, and the availability of guided tours.

Outer Loch Roe is a boat-access reef dive located in Scapa Flow. The site features depths ranging from 12 to 18 metres, with an average depth of 15 metres. Divers can expect mild currents and visibility between 5 and 10 metres. Water temperatures fluctuate between 8C and 14C, necessitating the use of a dry suit. Due to the presence of surf and strong currents, this site is suited for intermediate divers. Boat access is required, and divers should conduct a thorough surface assessment before entry. Typical dive times are approximately 45 minutes.

Achmelvich Bay is a shore-entry snorkelling site located in the West Highlands of Scotland. The bay is characterised by white shell-sand and rocky outcrops situated on either side of the beach. It is suitable for beginners and offers a 5/5 rating for snorkelling activities. Water temperatures vary throughout the year, ranging from 8C in the late winter months to 14C in August. Divers and snorkellers should be prepared for temperate marine conditions when exploring the rocky areas surrounding the bay.