

Best for beginner divers, shore entry.
Forme 4 is a unique flooded dry dock located within the port of Dunkerque, France. This site functions as a sheltered seawater pool, providing a controlled environment for snorkelling that is distinct from the open sea. The topography features submerged industrial relics, offering an unusual underwater landscape. Water temperatures vary significantly throughout the year, ranging from 8C in late winter to 19C in late summer. Due to its protected nature, the site is suitable for beginners. The habitat supports a variety of temperate marine life, including various crustaceans, cephalopods, and bottom-dwelling fish species typical of the region.
51.04389, 2.37000
Make sure you can join a permit holder who will call the harbor master upon arrival.
Enter the site via a concrete staircase after signing in with the harbor master.
Recorded at this site
Skill Level
Beginner
Entry
Shore
Water Temp
8-19°C
Yes, the site is suitable for beginners as it is a sheltered, flooded dry dock that provides a controlled environment.
Yes, Forme 4 is an established location for snorkelling with a rating of 3 out of 5.
Access to the water at Forme 4 is from the shore.
The habitat supports temperate marine life including various invertebrates, crustaceans, and bottom-dwelling fish species.
Water temperatures range from 8C in February and March to 19C in August and September.
Diving at Forme 4 in Dunkerque requires the following certifications: Permit Required. Always dive within your training limits.
A drysuit recommended is recommended for diving at Forme 4 in Dunkerque. Water temperatures range from 8°C to 19°C.
Divers at Forme 4 in Dunkerque should be aware of stonefish. These encounters are generally rare and avoidable with proper awareness. Follow local safety guidance and maintain a respectful distance from all marine life.