The first time I saw a magenta-hatched box stamped right across my planned track off the Var coast, I assumed it was an old chart artefact. It was not. It was a live missile testing range, and had I sailed through it on the wrong afternoon I would have had a grey hull telling me, very firmly, to leave. France keeps a busy military coastline, and the zones are scattered from the Channel to the Mediterranean. None of them are hidden. The trick is knowing how to read them and where the day's information actually lives.
Why there are so many of them
France has a large navy, two big naval ports, a submarine base and an active air force, and it tests weapons at sea. The result is a coast peppered with prohibited and restricted areas: permanent exclusion zones around bases, and temporary zones that switch on and off for firing practice, missile trials, parachute drops and diving. The permanent ones are obvious. The temporary ones are the ones that catch visitors, because the box on the chart looks dormant until the morning it goes hot.
A few worth knowing by name before you cruise the relevant stretch:
- Ile Longue in the Rade de Brest is the French ballistic missile submarine base. There is a hard exclusion zone around it that you do not test.
- The waters off Lorient and Gavres in south Brittany hold long-standing naval gunnery and training sectors.
- Ile du Levant, off Hyeres in the Mediterranean, is a missile testing range. The restricted area runs up to 11 nautical miles seaward from the south side of the island and up to 2 miles off the north side, and it is not in force between 1 July and 31 August, which is precisely when most visitors are there.
That Levant detail is the kind of thing that decides a passage. If you are crossing to Porquerolles in June you plan around the range; in late July you can usually sail straight through. Off season, treat it as live unless a notice says otherwise.
How the notices reach you
The chart shows you where a zone is. It cannot tell you whether it is active today. That information comes through the AVURNAV system, the French urgent notices to mariners. The word is a contraction of "avis urgent aux navigateurs". The Prefecture maritime issues them: the Brest prefecture covers the Atlantic and Channel, and the Toulon prefecture covers the Mediterranean. Firing and exercise notices go out the same way.
You pick these up three ways. CROSS broadcasts navigational warnings on VHF after an announcement on channel 16, on a dedicated working channel for each stretch of coast, at scheduled times. NAVTEX carries the wider warnings if you have a receiver. And the Prefecture maritime websites publish the AVURNAV list, which is worth checking on your phone before a passage that clips a known range. If you are not yet fluent with the coastguard side of this, my guide to the French CROSS coastguard sets out which station owns which water and what channels they work.
The notices are issued in French. The format is fairly mechanical once you have seen a few: a zone name or chart reference, a set of corner coordinates, dates and times, and the activity. Even with schoolboy French you can extract the box and the hours. If you cannot, that is itself a reason to give the area a wide berth.
Reading the chart symbols
French charts and the SHOM electronic charts mark these areas clearly, but the symbology rewards a moment of study. Permanent prohibited areas show as a continuous magenta line, often with a "no entry" annotation. Restricted areas, where entry depends on activity, show with a dashed magenta line. A firing or exercise area will usually carry a label referencing the notice that controls it. The almanac entry for the region spells out the activating authority and the listening watch.
Do not assume the box on a small-scale passage chart is the whole story. Exercise areas sometimes extend beyond the printed box during major drills, and the AVURNAV will say so. The chart is the floor of your knowledge, not the ceiling.
What actually happens if you stray in
Most of the time, nothing dramatic, because most zones are inactive most of the time. The problem is the day one is live. You may be hailed on channel 16 by a patrol vessel or by CROSS and told to clear the area immediately, and you comply without debate. During a missile trial off Levant the whole sector is closed to navigation, anchoring, diving and swimming, and the navy enforces it. Sanctions for pushing into a sensitive military zone are not trivial, and "I did not understand the notice" is a poor defence when the box has been on the chart for decades.
The greater danger is simply being in the wrong patch of water when something is fired or dropped. These are live ranges. Treat an active firing zone the way you would treat a busy shipping lane: as somewhere you have no business being while it is working.
Building it into your passage plan
I now do three things before any leg that touches a military area.
First, I mark the permanent exclusion zones on my working chart in a colour I cannot ignore, and I route around them as fixed obstacles. They never switch off.
Second, the night before, I check the relevant Prefecture maritime AVURNAV list for any temporary firing or exercise notices on my track, and I note the times. If a range is hot during my window, I either reroute or shift my departure.
Third, I keep a listening watch on channel 16 and on the regional CROSS working channel through the passage, so that if a notice changes I hear it. The same discipline that keeps you safe near shipping keeps you safe near the navy. My piece on staying clear of commercial shipping in French approaches covers the watchkeeping habit in more detail, and it applies equally here.
One more practical point. If you do find yourself near a zone you are unsure about and you cannot raise anyone, the safest call is a securite or, if you are genuinely worried about your position relative to a live range, a call to CROSS for advice. There is no shame in asking. If anything goes wrong while you are out there, knowing the French distress and safety call procedure cold is worth more than any chart.
The Mediterranean is busier than people expect
British visitors tend to think of military zones as a Channel and Biscay problem, then arrive in the south and find the Mediterranean coast just as active. The Toulon prefecture controls a long list of exercise sectors strung between Marseille and the Italian border, because Toulon is the home port of the French fleet, including the aircraft carrier. The Ile du Levant range is the headline one for cruisers heading to the Hyeres islands, but there are gunnery and training sectors scattered along the Var and the Provence coast that switch on for drills.
The practical consequence is that the same checking routine you would run before crossing Biscay applies to a lazy hop between Riviera anchorages. If your route to Port-Cros or Porquerolles clips a sector, check the Toulon AVURNAV list the night before. In high summer many of the ranges stand down, which is why August feels clear, but a flat calm September afternoon can find a sector live with nobody else around to remind you. The boats that get caught in the Mediterranean are the ones lulled by the holiday atmosphere into treating the magenta boxes as someone else's concern.
There is also a seasonal rhythm worth internalising. The Levant restricted area stands down between 1 July and 31 August precisely because that is peak cruising season; outside those dates the navy reclaims the water. Read the dates on the chart note and on the notice together, because the chart tells you the default and the notice tells you the exception.
The mindset that keeps you out of it
French firing and exercise zones are not a trap laid for foreigners. They are published, charted and broadcast, and the systems that warn you are the same ones you should already be using for weather and shipping. The visitors who get caught are the ones who treat a magenta box as decoration and never check whether it is live. Read the chart, read the notice, listen to the radio, and route around the doubt. The navy will be firing whether you are watching or not. The only question is whether you are in the way.
