Ranolien is a reef site located 100 metres from the shore near Trebeurden. The reef lies at depths between 10 and 16 metres, with an average depth of 13 metres, making it suitable for beginner divers. Divers can access the site from both the shore and by boat. Visibility typically ranges from 5 to 10 metres, and the area experiences moderate currents. To ensure a comfortable dive, it is recommended to time entries around slack water. On-site facilities include parking, toilets, showers, changing rooms, air fills, equipment rental, a cafe, first aid, a dive shop, and boat charter services.

Crique du Squéouel is a coastal site situated on the Pink Granite Coast near Saint-Malo. This location offers depths ranging from 10 to 20 metres and is accessible via both shore and boat entries. Divers and snorkellers should anticipate moderate currents and visibility between 5 and 10 metres. Water temperatures remain cool throughout the year, fluctuating between 10C and 15C. The site is suitable for beginners, though users should remain aware of potential hazards including boat traffic, cold water temperatures, and sharp rock formations. The topography features rocky areas and kelp meadows typical of the region.

Ploum'Aqua is a shore-entry dive site in Saint-Malo, France, featuring a mix of reef and wreck topography. Suitable for beginners with an Open Water certification, the site offers a typical dive duration of 30 minutes. Divers may encounter European Common Cuttlefish, wrasses, cod, and various crabs including rock crabs and European green crabs. Other observed life includes snails, sea squirts, shanny, clingfish, and rockpool prawns, alongside soft coral. Water temperatures range from 10C to 18C, necessitating appropriate thermal protection. Entry requires caution due to surf and a significant shore break, and divers should monitor local conditions to manage moderate currents.

Cale De Ploumanac'h is a shore-entry dive site located near Saint-Malo, France, featuring a combination of reef and kelp forest topography. The site reaches depths between 9 and 20 metres, with an average depth of 12 metres. Divers should be prepared for strong currents and surf conditions, which require an intermediate skill level. Visibility typically ranges from 5 to 10 metres. Water temperatures are cool, fluctuating between 10C and 15C throughout the year. The site is equipped with nearby parking, toilets, showers, and changing rooms, and supports night diving. Dive shops in the area provide air fills, equipment rental, and guided tours.

Pors Mabo is a south-facing reef site located in Saint-Malo, France. This sheltered bay is known for its southern exposure, which provides relatively warmer conditions compared to surrounding areas. Snorkellers can explore the rocky edges of the bay, which offer a peaceful environment for beginners. Access is via a shore entry from the beach. Water temperatures range from 10C to 17C throughout the year, making the water cool for extended immersion. Facilities available at the site include parking, toilets, and a cafe. Due to the cool water temperatures, appropriate thermal protection is recommended for all in-water activities.

Le Castel in Saint-Malo is a protected Natural Area featuring extensive eelgrass beds and pink granite outcrops. This shore-entry site offers shallow waters starting from one metre, making it suitable for beginners and snorkellers. Conditions are generally calm with mild currents, providing a comfortable environment for exploration. Water temperatures range from 10C in March to 17C in August and September. Divers can expect typical dive durations of 45 minutes. On-site facilities include changing rooms, showers, air fills, equipment rental, and boat charter services provided by the local dive shop.

Île Milliau Passage is a submersible channel connecting the mainland to the island, offering a distinct environment of sandy patches and dense kelp forests. Located 100 metres from the shore, this site is suitable for intermediate divers and provides a high-quality snorkelling experience. Depths range from 1 to 8 metres, with an average of 4 metres. Divers should be prepared for strong currents and surf conditions. Water temperatures fluctuate between 10C and 16C, with summer peaks reaching up to 19C. Wetsuits are recommended for all activities. Access is via shore entry, and parking is available nearby for visitors.

Crique du Squeouel is a small creek located north of the port in Saint-Malo, France. The site features rocky walls that descend into sandy bottoms, providing a sheltered environment for snorkelling. Access is via the shore, and the site is best suited for intermediate snorkellers due to the variable conditions of the region. Water temperatures fluctuate between 10C and 17C throughout the year. Species recorded around this area include wrasses, European common cuttlefish, tompot blennies, sea stars, various crab species, soft corals, cod, spirographs, snails, sea squirts, and shannies.