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.

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.

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.

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.

Plage de Locmaria is a south-facing, horseshoe-shaped bay located on the Île de Groix. This reef site is well-protected from northern winds, making it a suitable location for beginners. Divers and snorkellers can explore the rocky outcrops situated on either side of the bay. Access is via the shore, and conditions generally feature mild currents, though surf can be a hazard. Water temperatures fluctuate throughout the year, ranging from 10C in February to 18C between July and September. Parking and a cafe are available for visitors at this location.