How Hard Is L'Ultra Marin Grand Raid 175km? (7 m/km, 77.4% Flat, and What 175km of Coastal Endurance Actually Demands)

At approximately km 114, runners cross the Gulf of Morbihan by boat from Locmariaquer to Port-Navalo (Arzon) — approximately a 10-minute crossing. This is a unique structural feature of the Grand Raid not present in other DTR database races: a mandatory ferry transfer built into the route, reflecting the geography of the Gulf where a direct coastal path would add significant distance. It creates a memorable mid-race moment — a brief respite on the water with 60km still to run.

Yes — the 2026 Grand Raid was sold out as of the most recent DTR check. When registration reopens (typically for the following year's edition), it is processed via the Klikego platform — note a €3 processing fee applies. At €168 entry (~€0.96/km), L'Ultra Marin is one of the most affordable UTMB 100M-qualifying races in Europe. Given the consistent annual sell-out, register as early as possible when the window opens. Check ultra-marin.fr for the latest registration status.

Yes. L'Ultra Marin Grand Raid 175km is a UTMB 100M Index race, confirmed across the 2022-2025 editions. Verify the 2026 UTMB Index points allocation at utmb.world before registering, as index values can change between editions. The race is also listed on ITRA; verify current ITRA points at itra.run.

Nantes (NTE) and Rennes (RNS) airports are both approximately 84 minutes from Vannes — the race is NOT IS FAR. Vannes is served by direct TGV and regional rail from both airports and from Paris, making the race accessible by public transport. Book accommodation well in advance: the 10,000-participant race weekend (June 25-28, 2026) fills Vannes hotels quickly. The race starts and finishes at Esplanade Simone Veil in central Vannes.

Demanding in a way that has nothing to do with gradient. The 175km course gains only ~1,220m D+ (~7 m/km) with 77.4% flat terrain and a distance-weighted average uphill gradient of 3.93% — one of the most runnable 175km profiles in the DTR database. The challenge is pure coastal endurance: varied surfaces (sandy beaches, salt marshes, forest, stone paths), a Friday evening start into the Breton night, tidal conditions on lower coastal paths, and a 42-hour time limit. Front runners finish in approximately 15 hours; most runners manage their pacing over 25-40 hours.