Pointe de Pen Men is a reef and wall site located at the western tip of Île de Groix. The topography features a wall dropping to a maximum depth of 22 metres, with an average depth of 15 metres. This site is accessible only by boat due to strong surf and shore breaks at the coast. Divers can expect mild currents and visibility ranging from 5 to 10 metres. Water temperatures fluctuate between 11 and 16 degrees Celsius throughout the year, necessitating appropriate thermal protection. The site is suitable for beginners, though divers should remain vigilant regarding potential entanglement hazards within the reef structures.

Poullziorek, also known as Tahiti Beach, is a reef site on the Île de Groix featuring white sand and a shallow depth range of 2 to 10 metres. With an average depth of 5 metres, it is well-suited for snorkeling, which is highly rated here. Access is via the shore, though divers and snorkellers should be aware of moderate currents, surf, and rip currents. The water is notably cold, ranging from 10C to 17C throughout the year. Species recorded around this area include wrasses, conger eels, various crabs, sea stars, and European common cuttlefish. Parking is available near the site.

Port Melin is a sheltered inlet on the Île de Groix, featuring a diverse underwater topography of rocky walls, reefs, and kelp forests. The site offers an average depth of 8 metres, with a range between 6 and 10 metres. Divers and snorkellers can explore the steep rocky walls that provide a vertical habitat for sponges and kelp. Access is via the shore, and the site is suited for intermediate divers due to moderate currents. Water temperatures fluctuate between 10C and 17C throughout the year. Typical dives last approximately 30 minutes.

Kelhuit is a reef dive located 800 metres off the coast of Île de Groix, France. This site is well suited for beginner divers, offering a shallow profile that ranges from 1 to 15 metres with an average depth of 8 metres. Access is by boat only. Divers can expect mild currents and visibility typically between 5 and 10 metres. The site is suitable for night diving, allowing for a different perspective of the reef structure. Water temperatures fluctuate between 10 and 17 degrees Celsius throughout the year, necessitating appropriate thermal protection such as a 7mm wetsuit during colder months. Typical dive duration is approximately 40 minutes.

Tahiti Beach on Île de Groix is a shallow reef site suitable for beginner divers. The site features a consistent depth of 6 metres and is accessed directly from the shore. Conditions are generally mild, though visibility can vary between 3 and 10 metres. Divers should be prepared for cold water temperatures, which range from 10°C to 17°C throughout the year. Facilities available at the site include parking, showers, and toilets. Due to the low water temperatures, appropriate thermal protection is recommended for all dives.

Port Lay is a sheltered reef site located on Île de Groix, France. Divers access the water from the shore behind the seawall, making it a suitable location for beginners. The site features depths ranging from 5 to 15 metres, with an average depth of 10 metres. Conditions are generally mild, though divers should remain aware of boat traffic in the area. Facilities available at the site include air fills, a dive shop, guided tours, parking, toilets, and showers. Night diving is possible here, and the site is also suitable for snorkelling. Species recorded around this area include wrasses, conger eels, sea stars, crabs, and various molluscs.

Plage des Kaolins on Île de Groix offers a reef environment accessible from the shore. The site features rocky sections at either end of a long sandy stretch, providing varied topography for snorkelers. Depths range from 1 to 15 metres, with an average depth of 5 metres. Conditions include moderate currents and potential surf, requiring intermediate skill levels. Visibility typically spans 5 to 10 metres. Water temperatures fluctuate between 10C and 18C, making cold water shock a consideration for those entering the water. Facilities at the site include parking, toilets, and showers.

Sperrbrecher 134 is a wreck dive located 800 metres off the coast of Île de Groix, France. The vessel rests at depths between 22 and 25 metres, with an average depth of 22 metres. Access is exclusively by boat charter. Divers encounter mild currents and visibility ranging from 3 to 10 metres. Due to the wreck structure, entanglement is a primary hazard, requiring careful navigation. Water temperatures remain between 10 and 15 degrees Celsius, necessitating a drysuit or a 7mm wetsuit with a hood. Carrying a primary and backup torch is recommended to assist with visibility when exploring the wreck's interior.