EstranIs it worth it, and when?
Estran checks the sea for you: tide, swell, wind, light. One verdict per spot, a window, and the reasons. Nothing else.
One-time purchase · no subscription · no account · no ads · no trackers
One idea: the foreshore.
The estran is the strip of beach the sea uncovers and reclaims twice a day — the window of a session, in other words. Estran is built around that curve — the day's tide, under a sky that follows the spot's real solar time — with swell, wind and light laid over it.
One glance, one answer
On the home screen, every spot says whether it's worth it today, at what time, and why. In a sentence, not a table.
Tides that are yours forever
We fitted our own harmonic constants to SHOM's open tide-gauge observations. Tides are computed on your phone: no network, no subscription, no drift.
Honest data
Sources named, freshness shown, uncertainty said out loud beyond three days. Never fake precision.
Made for the beach
Full-sun contrast, one hand, wet fingers. Lock-screen widgets with the next tide and the coefficient.
Tides you can check.
We fitted 57 harmonic constituents to two and a half years of hourly observations for each port, then verified the predictions on seven held-out months. At Brest, high-water times land within a minute of SHOM's tables, and the tide coefficient matches to the point. The full report is public.
| Port | HW/LW · median error | mean error | height · mean error |
|---|---|---|---|
| Brest | 0,1 min | 4,0 min | 14 cm |
| Saint-Malo | 1,4 min | 5,2 min | 18 cm |
| Roscoff | 0,1 min | 4,2 min | 17 cm |
| Les Sables-d'Olonne | 0,1 min | 7,2 min | 15 cm |
| Bayonne – Boucau | 0,0 min | 4,4 min | 11 cm |
| Saint-Jean-de-Luz – Socoa | 1,4 min | 5,2 min | 9 cm |
Errors measured over seven months of real observations (July 2025 – January 2026), which include weather: surges, pressure. Source: Shom/REFMAR, open licence. Computed by Estran.
Dunkirk · Calais · Boulogne · Dieppe · Le Havre · Cherbourg · Saint-Malo · Roscoff · Brest · Concarneau · Lorient · Saint-Nazaire · Les Sables · La Rochelle · Royan · Bayonne · Saint-Jean-de-Luz · Sète · Marseille · Toulon · Nice · Ajaccio…
One price. Once.
No subscription, no premium tier, no ads, no account. You buy the app, it's yours, and it still works in ten years on a beach with no signal. Family Sharing included.
Launch price announced at release. iPhone, iOS 26 and later.
Questions
Where do swell and wind forecasts come from?
From Open-Meteo, which assembles Météo-France models (AROME, ARPEGE, MFWAM) and ECMWF/Copernicus. Estran routes them through a small cache so the app stays fast and the subscription is on us, not you.
Are the tides SHOM's?
They are our own computations, from SHOM's open observations (REFMAR, open licence). Not an official SHOM prediction, but we publish our accuracy port by port. For navigation, use official documents.
Does it work offline?
Tides, yes, always. Swell and wind show the last forecast received, with its time.
Do you track my location?
No. Estran never asks for location: you pick your spots. And the app has no usage statistics and no trackers — nothing leaves your phone except the forecast request.
My spot isn't there.
Write to us: bonjour@estran.app. Every spot is reviewed with people who surf it before it's added.