The clearest water I have ever swum in was over a Posidonia meadow off Port-Cros, a grouper the size of a labrador watching me from a rock ledge, the sea so warm I forgot I was wearing a wetsuit. That is the reward for carrying decent snorkelling kit on a French cruise. The Mediterranean coast, the calanques, the Hyeres islands and Corsica are some of the finest cold-blooded swimming in Europe, and a tender plus a mask turns a quiet anchorage into an afternoon you remember for years.
But there is kit you carry for the swimming and kit you carry because French law expects it, and the second part trips up a lot of visiting boats. Here is the full list, the legal bits included, and how to stop it all turning to mould in a wet cockpit locker.
The swimming kit: buy decent, not cheap
A bad mask ruins snorkelling faster than anything. The single most common mistake is a cheap mask that leaks, and the fix costs only a little more.
- A tempered-glass mask that fits your face. Test the seal by holding it on without the strap and breathing in: a good fit holds itself. Carry a spare, because a snapped strap ends the day otherwise.
- A dry-top snorkel, which seals when a wave washes over it, far less mouthful-of-sea than a basic tube.
- Fins sized for bare feet or for the neoprene boots you actually wear. Open-heel adjustable fins with boots are the cruiser's choice because they double as deck footwear and protect against urchins ashore.
- A thin shorty wetsuit or a rash vest. Even in a record-warm Mediterranean summer, with sea-surface temperatures that hit a 26-degree average in 2025, an hour in the water cools you, and the neoprene also guards against sunburn and the odd jellyfish.
- A defogging cloth or a tiny bottle of mask defog, because nothing kills the magic like a fogged lens over a grouper.
That is perhaps 100 to 200 euros for a good adult set, and it lasts years if you rinse it.
The legal kit: the dive flag France insists on
This is the part nobody mentions until a harbour launch tells you off. In France, when you are in the water away from a marked swimming zone, you must mark your position with a buoy and flag so boats keep clear. Vessels are required to stay at least 100 metres clear of a displayed dive flag.
For a snorkeller off the boat that means a surface marker buoy, the inflatable tow-float kind with a small dive flag on it, on a line you trail or clip to yourself. It is cheap, it is high-visibility, and in a busy summer anchorage where tenders zip about it is genuinely protecting your head. Carry it and use it any time you swim away from the boat.
If anyone aboard is spearfishing, the flag is not optional, it is the law: a marker buoy with the alpha flag must be displayed. Read on for the spearfishing rules, because they are stricter than visitors expect.
Spearfishing and diving: the rules that catch people out
Spearfishing is popular and legal in France, but on tight conditions.
- You must spearfish on breath-hold only. Using scuba gear to spearfish is illegal across the EU, and so is spearfishing at night.
- You must carry third-party insurance. The simplest route is a membership of a French federation such as the FFESSM, FNPSA or FCSMP, which bundles the insurance and costs roughly 20 to 40 euros a year.
- You display the marker buoy and flag, and you keep well clear of marked swimming and bathing areas.
If you want to dive on bottled air rather than spear, that is a separate world with its own certification and centre-based rules, covered in our guide to scuba diving france certification. For most cruisers, breath-hold snorkelling over the reefs is the sweet spot: no certificate, no tanks, just the mask and the marker buoy.
Posidonia: swim over it, do not anchor on it
The seagrass that makes Mediterranean snorkelling so rich is also legally protected. Posidonia meadows grow from the shoreline down to around 25 metres, they are among the oldest living organisms on earth, and France has tightened anchoring rules to stop chains tearing them up. Since 2021 the largest yachts have been banned from anchoring on protected Posidonia beds, and the prefectoral rules have been extended since.
For a snorkeller this is pure upside: the meadows are the nurseries where the fish live. The point for your boat is to anchor on sand, not on the dark seagrass patches, both because it is the law for larger vessels and because it is better holding anyway. Read the bottom before you drop, swim down to check the anchor is in sand, and you protect both the meadow and your night's sleep.
Snorkelling with children aboard
Half the reason to carry snorkelling kit is that it keeps children happy at anchor for hours, and France is ideal for it: warm clear water, shallow rocky shores teeming with small fish, and plenty of sheltered bays. The kit changes a little for young swimmers. A child's mask must fit a small face properly, an adult mask leaks endlessly on a child and puts them off, so buy one sized for them rather than a hand-me-down. A buoyancy aid or a wetsuit adds flotation and warmth, both of which let a nervous swimmer relax and stay in longer.
The marker buoy matters even more with children in the water, because a small head is hard to spot among the chop and tender wash of a busy August anchorage. Keep the swimmers grouped near the buoy, brief them to surface and look around before they cross open water, and have an adult in the dinghy or on deck watching at all times. Snorkelling with kids in the calanques or off the Hyeres islands is one of the great low-cost pleasures of a French cruise, and a little structure round the safety side is what lets you actually relax while they explore.
Stowage: the enemy is salt and damp
Snorkelling kit lives wet, and wet salty neoprene in a closed locker grows mould and rots straps within a season. Beat it.
- Rinse everything in fresh water at the first opportunity, especially the mask skirt, the snorkel valve and the fin buckles, where salt crystallises and seizes.
- Stow it in a mesh bag, never a sealed dry bag, so it can breathe and finish drying.
- Hang the wetsuit over the boom or a guardrail to dry before it goes below, never folded damp.
- Keep the marker buoy and its line untangled in their own small bag, ready to grab, because a buoy you cannot find fast is a buoy you swim without.
Treat the rinse-and-hang routine as part of the same end-of-day discipline as the rest of your gear, alongside the boat refrigeration france load management and the wider boat spares kit france.
The set I carry, and what I would add
My standing kit is two adult masks plus a child's, two dry-top snorkels, open-heel fins with neoprene boots, two shorty wetsuits, a defog bottle, and one orange tow-float marker buoy with a small dive flag. I do not spearfish, so I skip the federation membership, but if you plan to take a fish off the rocks, sort the insurance before you leave home because a French-language certificate is awkward to arrange on the hoof.
The one upgrade I keep meaning to make is a second marker buoy, so two of us can be in the water in different spots without one person swimming unmarked. In a summer when the Hyeres and calanques anchorages are packed with tenders, being visible is not vanity, it is the cheapest insurance on the boat. Get the mask fit right, carry the flag, anchor off the seagrass, and the French Mediterranean gives back more underwater than almost anywhere in Europe.
