Baie d’Authie is a place to marvel at. Nestling between the Baie de Somme and the Côte d’Opale, this natural nugget covers roughly 2,100 to 2,200 hectares of protected estuary, dunes and marshland (Conservatoire du littoral, Hauts-de-France Tourisme). The Authie, a 105 km coastal river, marks the natural border between Berck in the Pas-de-Calais and Fort-Mahon-Plage in the Somme. Between the sea and the golden sand dunes, the bay is worth the detour on its own. Berck, Le Touquet and Paris Plage all make for a stopover full of discoveries in 2026.
An exceptional place: Authie Bay
The Baie d’Authie is a little treasure trove of nature, located between Berck and the Baie de Somme. It’s a paradise for birdwatchers, hikers and all nature lovers. The scenery ranges from the calm waters of the bay to the fine sand dunes and vast expanses of marshland.
The Baie d’Authie is also a favorite haunt for harbor and grey seals, which haul out on the sandbanks to rest as the tide drops. The sandbanks start to emerge around two and a half hours before low tide, which is the best window for a sighting (Passion Baie de Somme). A 2025 survey of the wider Baie de Somme / Baie d’Authie system counted around 400 harbor seal pups and 200 grey seals, though the animals move freely between both bays, so exact numbers on any given day vary. Guided walks organized by the local tourist offices let you approach the colony without disturbing it: expect from around 10€ per adult (5€ to 5.50€ per child) for a short 1h30 outing, up to around 16€ per adult for a longer 3-hour hike, with booking required (rates for the 2025-2026 season, check the tourist office site before you go).
Another major point of interest in the bay is the Parc de Marquenterre. Located in the heart of the Baie de Somme nature reserve, this ornithological park is a haven for migratory birds.
Baie d’Authie in 2026: what to check before you go
The bay floods twice a day, and the tidal range can reach up to 10 metres on the biggest spring tides (Fort-Mahon-Plage tourist office), so the water comes in fast. Never head out onto the flats on your own without checking the tide times first, and be aware of quicksand near the channels; a guided walk with a local tourist office is the safer option if you’re not familiar with the terrain.
Baie d’Authie and Baie de Somme are two separate estuaries with their own rules, which is a common source of confusion. For the 2026 season, recreational cockle gathering is banned on every bed of the Baie d’Authie, on both the Pas-de-Calais side (Berck, Groffliers, Waben) and the Somme side (Fort-Mahon-Plage), by order of the Pas-de-Calais prefecture, while the northern sector of the Baie de Somme stayed open to cockle gathering until 27 July 2026. Where cockle gathering is allowed, the legal minimum size is 2.7 cm. Check the current prefectural order before planning any shellfish gathering, since these rules can change from one season to the next.
Mahon beach: an unmissable stopover
Fort-Mahon-Plage, on the south bank of the Baie d’Authie in the Somme department (facing Berck in the Pas-de-Calais on the opposite shore), is the perfect place to relax and get away from it all. At low tide, the beach stretches as far as the eye can see, revealing vast stretches of fine sand ideal for strolling. At high tide, you can admire the reflection of the sun on the water.
This stretch of coast is also part of the seal colony’s territory: the animals haul out on the sandbanks visible from the dune as the tide drops (see the timing above). A pair of binoculars and a bit of patience go a long way.
The Dune d’Authie trail: an immersion in nature
The Dune d’Authie trail is a good way to see the bay on foot. Departing from Berck, this signposted hiking trail crosses the « Dunes de Baie d’Authie » natural area, 218 hectares owned by the Conservatoire du littoral and managed by Eden 62, with views over the bay and its wildlife along the way.
Along the way, you’ll be able to spot seal calves, migratory birds and Henson’s horses, an emblematic local breed once used to graze the dunes. If you’d rather go with a guide, the « Dunes de l’Authie » outing offered by the local tourist offices follows a similar route (roughly 3 hours, 5 km) and is worth booking ahead in high season.
Le Touquet-Paris-Plage: a chic, natural stopover
North of the Bay of Authie, Le Touquet-Paris-Plage is a leading destination on the Côte d’Opale. A chic and dynamic seaside resort, it offers a multitude of activities and discoveries, between beach, nature and heritage.
Just a stone’s throw from the Bay of Authie, the Le Touquet lighthouse offers a wide panorama over the Côte d’Opale and the Bay of Canche. The covered market in Le Touquet is worth a stop too, with its stalls of local produce.
Between the seals, the dunes and the shifting tides, the Baie d’Authie rewards a slow visit more than a rushed one. Plan around the tide table, book a guided walk if you want to get close to the seal colony, and check the current fishing rules before you pack a bucket and rake. A weekend split between Berck, Fort-Mahon-Plage and Le Touquet is enough to see the best of it in 2026.