Most cruisers do not need a satellite dish to stay online in France. They need to stop overpaying for the mobile data that is already in the air around them. After four seasons working down the French coast on a 38-foot boat, the bulk of my connectivity has come not from space but from a SIM card bought in a phone shop in La Rochelle and an antenna zip-tied to a stanchion.
This is the ground-level version: what the French networks actually deliver on the water, what it costs in 2026, and how to squeeze a usable signal further offshore than the marketing maps suggest.
The French networks are very good, on land
Start with the encouraging part. France has four mobile networks (Orange, SFR, Bouygues, Free), and the coverage is strong. Orange reaches roughly 99 percent of the population in 4G with 5G now over 60 percent, and Free Mobile claims around 99 percent 4G and about 95 percent 5G coverage, with the largest number of active 5G sites in the country.
For a boat, population coverage is not the same as water coverage, but it is a useful proxy: where there are people on the coast, there are masts pointed roughly your way. Tucked in a marina, motoring up a Brittany river, anchored off a busy bay, you will usually have fast data.
The catch, as always for visitors, is what you pay to use it.
The roaming trap (British sailors, read this)
If you are bringing a UK phone, your old EU roaming is gone. Since Brexit the UK is treated as a non-EU country for wholesale roaming, so the regulated price cap no longer protects you, and the big networks now charge a daily surcharge of roughly 2.00 to 2.57 pounds to use your home allowance in France. Over a three-month summer that is north of 200 pounds in fees alone.
It gets worse near the coast. A phone in a Cherbourg marina can latch onto a French or Channel Islands mast overnight and fire the daily charge while it sits in a drawer. If you keep a UK SIM for bank codes and calls, turn its mobile data off the moment you leave UK waters. I cover the full Brexit picture, connectivity included, in my piece on the SIM cards and data for cruising France, which is the companion to this one.
A French SIM: the value play for a season
For any stay beyond a few weeks, a French prepaid SIM is the obvious answer. The market is fiercely competitive, with Free Mobile having built its name on cheap data and the others following. Prepaid bundles of 20 to 50 GB typically sit in the 10 to 25 euro range per month, which is a fraction of what UK roaming costs over a season.
The hurdle is registration. French SIMs need identity verification, and the cheapest online-only deals often want a French bank card and address, which a transient boater does not have. My workaround: walk into an Orange, SFR or Bouygues shop in a decent town with my passport, let the staff activate it in store, and pay by card or cash. You pay slightly more than the online bargains, but you skip the address problem entirely. La Rochelle, Lorient and Brest all have shops near the marinas.
eSIM: the flexible option for border-hoppers
If your cruise crosses borders (Channel Islands, France, maybe Spain), an eSIM is the painless choice. No plastic, no shop, you buy it on the phone and it activates over the air.
Orange Holiday Europe is the one most cruisers reach for, a prepaid Europe plan covering dozens of countries, with data-only eSIMs starting around 4.99 to 6 dollars. Travel eSIM resellers go cheaper still, with small 1 GB short-duration plans from under 3 euros. For a two-week trip a few gigabytes on an eSIM works out at a tenth of pay-per-use roaming.
My standing setup: UK SIM live but data off for banking SMS, a French prepaid SIM for the data I burn on long stays, and an Orange eSIM for the border weeks. A dual-SIM phone makes the whole thing seamless.
Where the signal actually drops
The honest coverage map, learned by losing signal at the worst moments.
Mid-Channel you will lose 4G somewhere past 15 to 20 miles offshore. The Bay of Biscay offshore is simply dead, so plan for no data on a Biscay passage and download everything first. Off the Atlantic islands and behind granite headlands the bars come and go as the boat swings. The Mediterranean coast is dense with masts and strong close in, but heading offshore towards Corsica you will lose it well before you arrive.
This matters more than people admit, because so much modern passage planning assumes a live connection. Pull your GRIBs and routes before you slip the lines. The good weather-routing apps for Biscay and the Med all cache forecasts for offline use, and you should lean on that, not on hope.
Pulling signal further out: the external antenna trick
The single best upgrade for working afloat is a rail or masthead 4G/5G antenna feeding a small marine router. A phone buried in the cabin is a poor radio. A weatherproof external antenna with proper gain, mounted high and clear, pulls a usable signal several miles further offshore and turns marginal anchorages into working ones.
I run a cheap external antenna into a 4G router, perhaps 150 to 250 euros of kit, and it has paid for itself many times over. Drop your French SIM into the router rather than the phone, and the whole boat shares one strong connection.
A note on 5G: it is genuinely faster where you have it, but on the water the gain is patchy and the range is shorter than 4G, so do not buy a network plan purely chasing the 5G logo. Reliable 4G from a good antenna beats a flickering 5G bar every time.
How much data a cruising boat actually burns
People over-buy data out of anxiety, so a rough sense of real usage helps. A couple living aboard and doing the normal things, messaging, weather downloads, a film or two, light browsing, comfortably fits inside 20 to 30 GB a month. Add regular video calls or remote working and you climb towards 50 GB or more. Stream a lot of high-definition video and there is no upper limit, but that is a choice, not a necessity.
This is why a 20 to 50 GB French prepaid bundle at 10 to 25 euros a month suits most cruisers, and why the cheapest tiny eSIM plans only make sense for a short trip. Match the bundle to your habits: a season of working afloat wants a generous French SIM, a fortnight's holiday wants a modest eSIM, and almost nobody coastal needs the unlimited tiers the satellite plans push. Download charts and forecasts over wifi when you can, and your mobile allowance stretches a long way.
When mobile data is not enough
There is a line beyond which no land network reaches, and that is where satellite earns its keep. If you cross Biscay regularly, liveaboard offshore or work full time from genuinely remote anchorages, the case for Starlink on a boat in France becomes real, and the Mini on a Roam plan has dropped in price enough to tempt a lot of cruisers. For the rest of us, mostly inshore in France, a French SIM plus an antenna does the job for a fraction of the outlay.
The plan I would hand a friend
Arriving from the UK for a full season:
- Keep your UK SIM active but data off. Never leave roaming data on by accident.
- For stays over a month, buy a French prepaid SIM in a carrier shop with your passport. Best value for the data you will use.
- For short or border-hopping trips, an Orange Holiday eSIM bought before you leave home.
- Add a rail-mounted external antenna and a small router if you work afloat.
- Download charts, forecasts and offline material before every passage, because the dead zones are real and predictable.
One last rule, learned the hard way: treat marina wifi as a bonus, never a plan. The capitainerie router at a packed July port is shared among a hundred streaming boats and crawls. Your own data is what keeps the boat connected.
