One of France's great tidal landscapes, 2 hours north of Paris: a wild seal colony you watch from a shingle bank for free, a bird sanctuary with 300+ species, a steam train along the shore, and endless flat cycling around the bay.
The Somme estuary is one of the largest and best-preserved tidal bays in France — 70 km² of sandbanks, salt marsh and mudflats that empty and refill twice a day. It's the only spot within a weekend's reach of Paris where you can watch a genuinely wild colony of harbour and grey seals hauled out on a shingle bank, no boat or guide required. Add the Parc du Marquenterre bird reserve (one of the top birdwatching sites in Europe, on a major migration flyway), a narrow-gauge steam train that runs along the bay shore, medieval Saint-Valery-sur-Somme (where William the Conqueror set sail for England in 1066), and a flat, wind-blown network of cycling paths circling the whole bay — it's a complete, low-effort nature weekend.
Drive up Friday evening or early Saturday — the route runs mostly via the A16 (light tolls, roughly €10). Base yourself in Le Crotoy, the sandy-beach town on the north shore of the bay, small and walkable with a working fishing harbour. Spend the afternoon at the Pointe du Hourdel, the classic wild seal-watching spot on the south shore: park free at the entrance to the Route Blanche (shared car-park/motorhome area) and walk out onto the shingle dike. Seals haul out roughly 3 hours before to 2h30 after low tide — arrive about 1h30 before low tide and settle near the old blockhouse by the channel; retreat to dry land as the tide starts to turn (~3h30 before high tide). No guide or ticket needed, and binoculars help but aren't essential.
Morning at the Parc du Marquenterre bird reserve in Saint-Quentin-en-Tourmont — three marked loops (45 min, 1h30, or 2h full loop) through dunes, marsh and lagoons packed with storks, spoonbills, avocets and migrating waders; adult entry €12, free parking. In the afternoon, ride the Chemin de Fer de la Baie de Somme, the vintage steam/diesel train that runs along the shoreline between Le Crotoy, Noyelles and Saint-Valery — round-trip tickets from about €16, full fares roughly €13–25 depending on the route. Get off in Saint-Valery-sur-Somme to walk the cobbled Cité Médiévale ramparts and the fishermen's quarter before heading back.
The bay is one of the flattest, most bike-friendly areas within reach of Paris — a marked network of cycling routes (part of the EuroVelo 4 corridor) circles the whole estuary, linking Le Crotoy, Saint-Valery, Noyelles and the Marquenterre park on quiet lanes and dedicated paths, with almost no elevation gain. Bike loaded inside per the Car Camping & Bike Guide — no rack needed. A ride around the bay (or combined with the steam train one-way, bike back the other) is a great way to fill a spare morning.
| Category | Cost |
|---|---|
| Tolls (A16, round trip) | ≈ €15–20 |
| Charging (home charge before/after; optional slow top-up via aire's paid electric hookup) | €0–5 |
| Lodging (2 nights, Le Crotoy aire) | ≈ €20–26 |
| Parc du Marquenterre entry | ≈ €12 |
| Chemin de Fer de la Baie de Somme (round trip) | ≈ €16–20 |
| Treat meal — agneau de pré-salé | ≈ €26–32 |
| Food (self-cooked, rest of trip) | ≈ €20–25 |
| Total | €90–130 |