Mellon Charles is an artificial reef site located in Scapa Flow, consisting of the submerged remains of a former WWII naval base. Divers can explore the old pier structures, which are situated approximately 90 metres from the shore. The site is suitable for beginners, offering a shallow average depth of 6 metres with a range of 3 to 8 metres. Conditions include mild currents and visibility between 3 and 10 metres. Water temperatures fluctuate between 8C and 14C throughout the year. Entry is from the shore, and the site is also well-suited for snorkelling. Hazards include boat traffic and the presence of jellyfish.

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.

Toscaig Pier is a shore-entry reef site located on the Applecross peninsula. The topography features rocky nooks and crannies that provide habitat for small marine life. Divers and snorkellers can explore depths ranging from 0 to 30 metres, with an average depth of 8 metres. Conditions are variable, with visibility typically between 1 and 15 metres and mild currents. The water temperature remains cold throughout the year, ranging from 8C to 13C, necessitating appropriate thermal protection. The site is suitable for beginners, though users should remain aware of boat traffic and potential entanglement hazards in the area. Parking facilities are available near the pier.