French Oysters, four coasts to eat them where they are raised.

What are French oysters?

It is not a region, but a trip with a purpose. France raises oysters along almost all its coast, from the Channel to the Mediterranean, and in each place they are raised, refined and eaten differently. At Geocalia we bring together four places where the oyster is not just another dish on the menu, but the reason to go: the producer opens it in front of you, a few metres from the bed where it grew, and you eat it with bread, butter and a glass of white wine.

The four are Cancale, in the bay of Mont-Saint-Michel; Marennes-Oléron, the marshland of the claires in Charente-Maritime; the Arcachon Bay, south of Bordeaux; and Bouzigues, on the shore of the Étang de Thau, already on the Mediterranean. Normandy, southern Brittany and the Vendée coast also produce a lot of oysters, but here we stick with the places where eating them by the water is the main experience.

How is each coast different?

At Cancale the tide is enormous and the beds are left exposed at low tide, in view from the quay. At the market in the port of La Houle you buy a dozen from the producers, they open it for you and you eat it on the steps of the jetty. It is also one of the few places where you often see the flat oyster, dearer and more mineral in flavour than the cupped one.

At Marennes-Oléron the speciality is the finishing. The oysters grow in the sea and then spend weeks in the claires, clay ponds in the marsh, where they lose salt and gain flavour. From there come the fine de claire and the spéciale de claire. The DIRM Sud-Atlantique describes it as the largest centre for finishing and marketing oysters in France. They are eaten in the coloured huts along the channels and the area is toured by bike.

At Arcachon the bay is the great cradle of the country's natural oyster: much of the spat that other ports raise comes from its waters. Tasting is done in the huts of the oyster-farming villages, on the Cap Ferret peninsula or in the port of Larros, often with country pâté alongside, which here accompanies the oyster. At the bay's entrance is the Pilat dune.

At the Étang de Thau there are no tides. The oysters grow hanging from ropes beneath the tables, structures driven into the lagoon, and turn out fleshier and less salty than the Atlantic ones. They are eaten at the producers' farmsteads (mas) in Bouzigues, Mèze or Marseillan, with grilled mussels and local white wine.

How is the trip done?

By car, which is the practical way because the producers are outside the town centres. The four stops are linked from north to south along the Atlantic coast and then you cross to the Mediterranean. From Cancale to Marennes it is about 370 km, between four and a half and five hours by road. From Marennes to Arcachon, about 225 km and a little under three hours, passing through Bordeaux or going round the Gironde estuary. From Arcachon to Bouzigues, the long leap: over 500 km and about five and a half hours via Toulouse.

From Spain it is easier to do it the other way round or in parts. Arcachon is about 220 km from Irún, a little over two hours, and Bouzigues about 325 km from Barcelona, about three and a half hours. Many travellers combine only two: Arcachon and Marennes on the same Atlantic trip, or Thau with Sète and Montpellier on a getaway from Catalonia. Cancale fits better into a trip through Brittany and Normandy with Mont-Saint-Michel.

Without a car you can reach each place separately: there is a train from Bordeaux to Arcachon, from Montpellier to Sète and from Paris to Rennes or Saint-Malo, and from there a bus. But going from hut to hut without a vehicle is hard, except in Arcachon and Oléron, where the bike really works.

When to go and how many days?

Oysters are available all year on the four coasts. The saying about eating them only in months with an "r" dates from when there was no cold to transport them. What does change is the oyster: in summer the natural one spawns and becomes milky, and many producers then serve triploids, which do not. To eat them at their best, from September to April.

The best times to travel are April, May, September and October: the oyster is good, the huts open and there are none of the July and August crowds. In winter you eat very well, especially at Christmas, when a good part of the year's oysters are eaten, but many huts in Marennes and Arcachon close or open only at weekends. In Thau, in high summer, the warm water can leave the lagoon without oxygen and kill oysters.

For all four coasts, a week with a lot of road; better ten days. For two of them, four or five days. Cancale can be seen in half a day, although it calls for combining with Saint-Malo and the bay; Marennes-Oléron and Arcachon call for two days each; Bouzigues and the lagoon, one or two.

What is worth knowing beforehand?

The oyster's number is its weight: the lower it is, the bigger. No. 3 is the everyday size. Fine and spéciale are not sizes, but how much flesh the oyster has. At a producer's, a dozen costs from about €6 on the Cancale quay and from about €7 in an Oléron hut; in Arcachon, between €10 and €13; in Thau, from €1 apiece. Each hut closes some day and some only take cash.

Before going, check whether there is a health closure. The prefectures sometimes ban the sale of shellfish from a bay for days or weeks, as happened in Arcachon in the winter of 2023 because of norovirus.