Anchoring without damaging Posidonia: the 2026 rules
In the Mediterranean, anchoring on a Posidonia seagrass meadow is prohibited whenever the anchor could damage it, whatever the size of the boat. So you drop anchor on sand, which is lighter in colour, you raise it by positioning the boat above it, and in a ZMEL you pick up a buoy. Posidonia is a protected species: damaging it can lead to penalties of up to a €150,000 fine.
Why the seagrass meadow matters
- Posidonia covers between 20 and 50% of the coastal seabed, and its meadows are home to more than 20% of Mediterranean biodiversity (French Office for Biodiversity).
- Its rhizome grows by about 1 cm a year: an anchor scar takes decades to close up (French Maritime Prefecture).
- The seagrass meadows of the French Mediterranean have lost 10% of their area in a century (OFB); the DIRM describes their destruction as “virtually irreversible” (DIRM Méditerranée).
What the law says, depending on the size of the boat
| Boat | Rule |
|---|---|
| All | Anchoring is prohibited in a habitat of protected marine plant species when doing so could harm it (order 123/2019, art. 6.2). This is the rule for a rental boat. |
| 20 m and over, Alpes-Maritimes | From the Var to the Italian border, anchoring only seaward of a set limit (order 204/2020). |
| 24 m and over | Local orders set a limit beyond which alone anchoring is allowed. |
| 45 m and over | Mandatory anchoring zones; declaration to the signal station one hour beforehand (45 to 80 m) or authorisation (80 m and over) (order 157/2024). |
The species itself has been protected throughout France since 1988: it is prohibited to destroy all or part of it (ministerial order of 19 July 1988).
72 hours in the same place — and never on the seagrass
A leisure boat may stay 72 hours at the same anchorage. After that, a boat under 24 m without AIS must leave, unless the weather is dangerous, and may not return straight away within a 500 m radius (order 77/2025). This time limit never opens the seagrass meadow to anchoring: it comes on top of the ban, it does not replace it.
Finding sand, setting and raising the anchor
- Look for the light patches: sandy areas are generally lighter than the dark seagrass meadow (OFB).
- Prepare with a chart: the DONIA app, cited by the French Maritime Prefecture and the OFB, provides seabed maps free of charge; SHOM charts are the only authoritative ones (French Maritime Prefecture). The DIRM publishes the sensitive sites by département (Alpes-Maritimes, Var).
- Pick up a buoy when there is one: in a ZMEL, anchoring is prohibited.
- Raise the anchor by positioning the boat above it: if you reverse to tighten the chain, the boat drags its anchor, which ploughs a furrow and tears out clumps of seagrass (French Maritime Prefecture).
What boaters risk
- Failing to respect a prohibited zone: one year’s imprisonment and a €150,000 fine (Transport Code, art. L5242-2).
- Harming a protected species, intentionally or through gross negligence: three years and €150,000 (Environment Code, art. L415-3).
- In November 2024, the Marseille maritime court sentenced the captain of a 26 m yacht to a €20,000 fine and €86,537 in ecological damages for anchoring in the seagrass meadow (French Maritime Prefecture).
ZMELs: buoys to protect the seagrass meadow
A ZMEL (organised mooring buoys) replaces anchors with buoys, to limit uncontrolled anchoring (French Ministry for the Sea). On the Côte d’Azur, Pampelonne, the Villefranche roadstead, the anse du Croûton and the anse Sainte-Anne at Lérins each have one: their policing regulations are authoritative, and anchoring there is prohibited — see the Coves and anchorages guide.
Frequently asked questions
Can you drop anchor on Posidonia?
No, as soon as the anchor could damage the seagrass meadow, which in practice it does. Order 123/2019 prohibits it for all boats, and Posidonia is a protected species.
How do I know if I am over sand?
Sand looks lighter than the seagrass meadow, which is dark. Plan your stop with the DONIA app or SHOM charts, and pick up a buoy when there is one.
What is the fine for anchoring on Posidonia?
Up to a €150,000 fine, and one to three years’ imprisonment depending on the offence; ecological damages may be added, as the Marseille maritime court ruled in 2024.
Official sources
- Prefectoral order 123/2019 — anchoring of vessels
- Prefectoral order 77/2025 — anchoring duration
- Prefectoral order 157/2024 — vessels of 45 m and over
- Ministerial order of 19 July 1988 — protected marine plant species
- OFB — Posidonia seagrass meadows
- French Maritime Prefecture — J’aime la Méditerranée
- DIRM Méditerranée — anchoring strategy
- French Maritime Prefecture — ruling of the Marseille maritime court
Sources consulted on 26 September 2026. This guide helps you prepare a trip; it replaces neither the texts in force, nor the rental company’s instructions, nor the day’s weather forecast.