The bay I love most on the French Med coast is a small one, a horseshoe of clear water under pines, and the reason I love it is that it still feels untouched. The reason it still feels untouched is that, mostly, the boats that use it have learned to take their mess away with them. Leaving no trace at anchor is not a slogan borrowed from hikers. On a boat it is a set of specific, learnable habits, several of which are now backed by French law.
Walkers have an easy job: they carry their rubbish out in a rucksack. A boat is harder, because the obvious place to put everything (food scraps, washing water, toilet waste, the lot) is the water you are floating in. Resisting that temptation is the whole discipline.
The seabed is not yours to scar
The trace that lasts longest is the one you cannot see you are leaving: the gouge an anchor and chain cut across a living seabed. On the Mediterranean coast that seabed is often Posidonia oceanica, the seagrass that grows only a few centimetres a year, so a scar carved in seconds can take decades to heal.
France now enforces this. Anchoring on Posidonia is banned for vessels over 24 metres, with fines reaching 150,000 euros and the threat of a ban from French waters for serious cases. Smaller boats are increasingly held to the same principle, and the only safe assumption in any Med bay with a grassy bottom is that it may be regulated. The skill is to read the seabed and drop on sand, which I set out in detail in my guide to low-impact anchoring to protect wildlife, and the legal background is in my notes on the Posidonia anchoring ban in France.
Black water: hold it, do not dump it
This is the one that surprises visiting boaters most, because the rules are stricter than many home waters and they are enforced.
Under the French Tourism Code, any boat built after 2008 and fitted with a toilet must have a holding tank or an approved treatment system to enter French sea ports, river ports, marinas, moorings or anchorages. In return, ports and marinas are required to provide pump-out facilities. Discharging waste water inside ports, marinas and designated anchorages is prohibited, and a pleasure boat under 20 metres can be fined up to 4,000 euros for dumping waste at sea. In canals and rivers, discharge is banned outright.
At sea, treated black water may be discharged beyond 3 miles from shore, and only while making at least 4 knots so it disperses. The practical rule for a night at anchor is simple: hold everything in the tank, and pump out ashore the next time you are alongside a marina with a pump-out point. Older boats with no tank are expected to use the toilets ashore.
For visiting boaters this catches people out in two ways. First, the popular bays are almost always inside the 3-mile line, so the open-sea discharge allowance simply does not apply where you actually anchor. Second, a holding tank is only useful if you can empty it, and pump-out points are still patchy along stretches of the French coast despite the legal requirement for ports to provide them. The fix is to plan tank capacity around your cruise: know roughly how many days your tank lasts for your crew, mark the marinas that have a working pump-out, and empty when you are alongside rather than waiting until the tank is full and the temptation to dump is strongest.
What goes over the side, and what does not
Beyond the holding tank, a string of smaller habits decides whether you leave a trace.
- Galley scraps. A handful of crumbs is one thing; tipping a bin of food waste over the side in a sheltered bay is another, and it draws gulls and fouls the water. Bag it and take it ashore.
- Washing-up and washing water. The soap, shampoo and detergent that go down a boat's drains end up in the bay. Switch to genuinely biodegradable, low-phosphate products, use them sparingly, and wash up with a fraction of the water you would use at home.
- Cigarette ends, bottle caps, sweet wrappers. The small stuff blows off cockpit tables and side decks constantly. A lidded bin in the cockpit catches most of it.
- Fishing line and tackle. Monofilament lasts for years and tangles wildlife. Never let an offcut go over the side.
On biodegradable products specifically, the labelling can mislead. A bottle marked "ecological" may still be high in phosphates or surfactants that feed algal blooms in an enclosed bay. Look for genuinely low-phosphate, plant-based detergents, and remember that the greenest version is using less of whatever you buy. A boat that washes up in a bowl of seawater with a drop of mild soap, rather than running a tap of fresh water over a sponge full of foam, puts a tiny fraction of the chemical load into the anchorage. The habit is half the product and twice the rinse discipline.
Take it ashore properly
Leaving no trace at the anchorage only works if the rubbish actually leaves with you, rather than going from your bin to an overflowing harbour skip. French marinas and capitaineries provide sorted recycling and waste points, and on the Med many participate in schemes to collect used oil, flares and batteries as hazardous waste rather than landfill.
The honest move is to sort on board: a bag for recycling, a bag for general waste, a separate stash for anything hazardous, and to land each in the right bin. It takes a minute and it is the difference between genuinely removing your trace and simply relocating it. The wider picture of what marina services handle is in my guide to French marina water, electricity and showers.
The quiet part: noise, wake and wildlife
Not every trace is physical. Arriving at speed throws a wake that stirs sediment and rocks every anchored boat; a generator running all evening pollutes the calm as surely as it pollutes the air. Slow right down on approach, keep engine and genset hours to the minimum, and give hauled-out seals and nesting birds a wide, quiet berth.
If you cruise inside a national park or reserve, the bar is higher still, and the rules are firmer. I cover what a protected zone expects in my notes on marine protected areas and your responsibilities.
Wake deserves a second mention because it is the trace people least expect to be leaving. A planing boat or a heavy displacement yacht arriving at speed throws a wash that does not just rock the anchored fleet; in water shallower than about 5 metres it reaches the bottom, stirring sediment and, over a busy season, scouring the seabed in the approaches to a popular bay. Dropping to a slow, no-wake speed a few hundred metres out costs you a minute and removes the problem entirely. The same restraint applies to the tender: a dinghy buzzing back and forth to the beach at full throttle is its own small disturbance to swimmers, wildlife and everyone else's peace.
It adds up to almost nothing, and to everything
None of this is hard or expensive. A holding tank you already have, biodegradable washing-up liquid costs the same as the harsh stuff, a lidded bin is a few euros, and slowing down on approach is free. Put together, these habits mean you can spend a night in the most beautiful bay on the coast and leave it exactly as you found it.
That horseshoe bay under the pines is still clear because enough boats do this. The fines and the holding-tank law set the floor. The trace you actually leave, or do not, is decided by the small choices nobody is watching you make.
