Brest tide times

Brest occupies the north shore of the Rade de Brest — a large, semi-enclosed roadstead on the western tip of Brittany — and its tide gauge has been recording sea level without interruption since 1807. That record is not a footnote: it is the foundation for the French national geodetic datum and contributes to the global long-term sea-level datasets used in climate research. The tide at Brest is itself significant.

5 metres. 5 metres. The full variation across the tidal cycle from lowest neap to highest spring is among the largest in France, exceeded in continental Europe only by the Bay of Mont Saint-Michel 80 kilometres to the northeast.

8 kilometres wide at its narrowest and 25 metres deep. All tidal exchange between the Rade and the Iroise Sea passes through this bottleneck. On a spring ebb, the current in the Goulet runs at 4 to 5 knots; the surface over the northern shallows becomes choppy in any wind opposing the stream.

The Goulet's defensibility — one narrow entrance, easily watched, easily blocked — explains why the French Navy established its Atlantic headquarters at Brest in the 17th century. The military presence remains; the southern shore of the Rade is still a restricted zone, and the naval base is among the largest in Europe. For kayakers, the Rade is a genuinely rewarding paddling environment when the Goulet is avoided or timed correctly.

The sheltered inner bay allows multi-day circuits of the coastline, passing the Presqu'île de Crozon to the south and the Élorn river estuary to the east. The Élorn, which drains inland toward Landerneau, carries the tidal signal several kilometres upstream — the river is navigable by small craft on the flood and drains toward mudflats on the ebb. The oyster and mussel farms operating on the intertidal areas of the Rade and the adjacent Aulne river estuary depend on the predictability of the tidal cycle, and their lay-out — long lines of posts and cages across the sand and mud — is visible from the shore at any state of low tide.

South of Finistère, Point du Raz is the tip of the Cap Sizun headland where the coast turns the corner toward the Bay of Biscay. Between the Pointe and the Île de Sein — a low, flat island sitting in the middle of the Raz de Sein — the tidal race runs at up to 8 knots on spring tides. The Chaussée de Sein, the submerged reef field extending northwest of the island, has wrecked vessels for centuries; the Phare d'Ar-Men, built on an isolated rock at the western end of the reef, took 14 years to construct given the tidal and sea-state conditions during construction.

The Iroise Marine Natural Park, formally designated in 2007, encompasses the Île d'Ouessant, the Île de Sein, the Chaussée, and the open Iroise Sea out to the limit of territorial waters. It is among the largest marine protected areas in France. The park's boundaries are defined partly by the tidal races and reef systems that make this corner of Brittany one of the most dynamic marine environments in Europe.

Anglers working the rocky intertidal and subtidal ground around the Pointe du Raz and the coast south of Brest target bass, pollack, and wrasse. The relationship between tidal state and fish position on this coast is direct: the tidal current over the shallow reefs concentrates baitfish and the predators follow. Timing a session around the two-hour window either side of mid-flood or mid-ebb at the right location is the practical skill that separates consistent anglers from occasional ones.

The predictions on this page come from Open-Meteo Marine, a gridded global ocean model. 3 metres on height — model-derived, not a local gauge. 5-metre spring range, the height uncertainty is proportionally small, making these predictions a reliable reference for planning.

Authoritative data comes from SHOM, which operates the Brest gauge and publishes the official French tide tables. Brest also contributes to the Permanent Service for Mean Sea Level (PSMSL) global archive.