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.

The U 171 wreck is a deep-water dive site located 2000 metres off the coast of Île de Groix, France. This site is reserved for advanced divers due to its depth, which ranges from 18 to 40 metres with an average of 38 metres. Access is strictly by boat. Divers should be aware of the risk of entanglement when exploring the wreck structure. Visibility at the site fluctuates between 5 and 25 metres, and water temperatures remain cool, ranging from 11 to 15 degrees Celsius throughout the year. Typical bottom time for this dive is approximately 40 minutes.

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.

Locmaria Bay is a sheltered location on the south coast of the Île de Groix, France. The site features a gentle slope, making it suitable for beginners. Its position provides protection from prevailing northern winds, creating relatively calm conditions for snorkelling. The bay is characterised by rocky edges that define its topography. Water temperatures at this site vary throughout the year, ranging from 10C in February to 18C during the summer months of July, August, and September. Access to the water is via the shore.