Port-Marie, located in the Chausey archipelago, features a combination of reef and seagrass habitats. The site is suitable for beginners and offers a shallow average depth of 3 metres, with a total range between 1 and 5 metres. Access is via the shore, though the site is situated 17,000 metres from the mainland. Divers and snorkellers should be aware of strong currents present in the area. Visibility typically ranges from 10 to 20 metres. Water temperatures fluctuate throughout the year, peaking at 19°C in late summer and dropping to 9°C in late winter. Toilets are available at the site.

Port Marie is a sheltered, lagoon-like bay situated within a granite archipelago in Normandy. Known for experiencing the highest tidal range in Europe, the site features extensive kelp forests that provide habitat for a variety of marine life. Snorkellers can expect to encounter general temperate marine species typical of the region, including various invertebrates and fish associated with kelp environments. Access to the water is possible from both the shore and by boat. Due to the tidal conditions and the nature of the environment, this site is best suited for intermediate-level snorkellers. Water temperatures fluctuate throughout the year, ranging from 9C in the winter months to 19C during late summer.

Havre de Rothéneuf is a protected natural harbour in Saint-Malo, offering a sheltered environment that remains calm even when conditions in the open sea are rough. The site features a sandy bottom interspersed with rocky patches, making it a suitable location for beginners and families to snorkel from the shore. Water temperatures vary seasonally, ranging from 9C in February to 19C in August and September. Facilities available at the site include toilets and a rinse station. Species recorded around this area include European Common Cuttlefish, catsharks, sea slugs, squat lobsters, wrasses, conger eels, common lobsters, spiny spider crabs, and various sea stars.

The Walter is a wreck dive located off Saint-Malo, resting at depths between 30 and 38 metres. This site is suited for intermediate divers who possess both Open Water and wreck qualifications. Divers access the wreck by boat, encountering moderate currents that can strengthen during ascent and descent. Visibility typically ranges from 5 to 10 metres, requiring careful navigation around the structure. Water temperatures are cold, fluctuating between 9 and 15 degrees Celsius throughout the year, necessitating appropriate thermal protection. Due to the depth and potential for entanglement in wreckage components, precise buoyancy control and the use of a cutting tool are essential safety practices for all visitors.

The Hinrich is a wreck dive located off Saint-Malo, France, resting at depths between 23 and 41 metres. This site is suited for intermediate divers due to the depth and the presence of moderate currents that can strengthen quickly. Visibility typically ranges from 5 to 10 metres, requiring methodical navigation through the structure. Given the water temperatures of 9 to 15 degrees Celsius, a drysuit or thick wetsuit is necessary. Access is by boat only. Divers should monitor depth gauges closely, manage potential entanglement risks, and use a surface marker buoy for a controlled ascent due to local boat traffic.

Les Jardins de la Conchée is a boat-access site situated 4000 metres from the shore of Saint-Malo. The underwater topography features a complex environment of granite boulders and kelp gardens, alongside a wall, drop-off, and artificial reef structures. Divers can explore a wreck located within the site. Depths range from 4 to 25 metres, with an average depth of 20 metres. Conditions are variable, characterised by strong currents, surge, and surf, which require careful planning. Hazards include potential entanglement, boat traffic, and low visibility. This site is suitable for beginners, though the challenging currents necessitate caution.

Csce is a reef and wreck site located off the coast of Saint-Malo, France. Accessible only by boat, the site features depths ranging from 5 to 20 metres with an average of 12 metres. Divers encounter moderate currents and should be prepared for potential hazards including entanglement, low visibility, and surf. Marine life recorded here includes common spiny spider crabs and shrimp, alongside less frequent sightings of European common cuttlefish, squat lobsters, common lobsters, catsharks, wrasses, mantis shrimp, flatworms, conger eels, sea slugs, spirographs, pipefish, and abalone. Water temperatures vary from 9C to 15C, necessitating a 7mm wetsuit in summer and a waterproof suit with gloves and booties during spring and autumn.

Sprungturm is a marine dive site located in Saint-Malo, France, featuring a reef and drop-off topography. Divers can expect depths ranging from 12 to 15 metres, with an average depth of 13 metres. Access to the site is via the shore. Conditions at this location are variable, with visibility typically ranging between 5 and 15 metres and strong currents present. Facilities available at the site include changing rooms and showers. Due to the current and environmental conditions, this site is suited for intermediate divers.