How to stay connected on an island?

In the Canary Islands, Martinique or Madeira, an EU mobile plan works without you doing anything. In Zanzibar, the Maldives or Bali, it costs a fortune within minutes. And in Cuba, none of the usual solutions really works. Here is how to decide, island by island, before you leave.

The Dem-Tukki editorial team · 11 September 2026 · 9 min read

Getting connected has become the first reflex of the traveller who lands: let loved ones know, open a map, find the address of the accommodation. It is also the easiest expense to blow up without noticing — and the simplest to sort out, provided you do it before boarding.

📶 First question: is your plan enough?

Before looking for a solution, check whether you have a problem. Since 2017, the European principle of “roam like at home” requires operators to apply your home plan, at no extra cost, throughout the European Union and the European Economic Area — Norway and Iceland included.

What many travellers don't know is that five French overseas departments fall under the same rules : Guadeloupe, Martinique, French Guiana, Réunion and Mayotte. As EU outermost regions, they are covered by EU roaming for any EU plan: travelling to Martinique requires no particular step.

Two caveats, though. First, operators apply afair use policy: the data allowance usable abroad is often smaller than your plan's, and you get a warning text before being charged by the gigabyte. Second, Saint-Martin, Saint-Barthélemy and Saint-Pierre-et-Miquelon depend on each operator's policy — check in your customer account before you leave, without assuming it's included.

On the other hand, French Polynesia, New Caledonia and Wallis and Futuna are outside any included zone. Charges go back to pay-as-you-use, at rates counted in euros per megabyte.

🗺️ Where it's included, where it isn't

Here is the situation for the destinations we cover, for a traveller with an EU mobile plan.

If your destination falls into the first three categories, you can stop here: your phone will work as it does at home. The rest of this guide is for everyone else.

💳 eSIM, explained

An eSIM is a digital SIM card: instead of inserting a piece of plastic, you download a profile onto your phone. It is the same technology as a classic SIM card, without the tray or the paperclip.

For a trip, the benefit fits into one sentence: you add a local data line without removing your main card. Your usual number stays active to receive calls and texts — your bank's code, for example — while browsing, maps and messaging go through the local line, at local rates.

Two points are often misunderstood. These travel plans are almost always data-only : no local number, no regular calls. You phone via WhatsApp, FaceTime or Signal, which suits the vast majority of trips but not someone who has to call a landline locally. And most are sold in dollars, with volumes in gigabytes over a fixed period — a seven-day plan starts at the first connection to the network, not at purchase.

📱 Is your phone compatible?

Two conditions, and the second is the one that most often gets in the way.

An eSIM-compatible device. In practice, iPhones from the XS and XR generation onwards, Google Pixels from the 3 onwards and Samsung Galaxy phones from the S20 onwards are compatible, as are most high-end models released since. Rather than looking for your model in a list, do the thirty-second test: on iPhone, open Settings → Mobile Data and look for “Add eSIM”; on Samsung, SIM Manager ; on Pixel, Network & internet → SIMs. If the option is there, you are compatible.

An unlocked phone. A device locked by an operator will refuse any foreign profile. This is common with phones bought on credit with a plan. Unlocking is free and requested from your operator, but allow a few days — hence the point of checking well before departure, not the day before.

Two caveats worth knowing: iPhones bought in mainland China have no eSIM, and some refurbished or imported models may be locked without the seller mentioning it.

🧭 The three classic mistakes

Buying far too much data. Apart from video streaming, a traveller uses between 200 and 500 MB a day: maps, messaging, social media, a few searches. Over ten days, 3 to 5 GB is plenty for most people. 20 GB plans sell well because they reassure, not because they get used.

Forgetting to turn off data on your main line. This is the costly mistake: the eSIM is installed, but your home line stays active for data and keeps charging roaming. In the settings, explicitly set the eSIM as your data line and turn off mobile data and roaming on your main line.

Waiting until you arrive. Buying an eSIM requires an internet connection. On landing, with no data and sometimes no working airport wifi, you are exactly in the situation you wanted to avoid.

⚙️ Installing at the right time

The right method comes in three steps. At home, before you leave : buy the plan and install the profile, on wifi, at your leisure. Installing does not start the countdown of days — the first connection to the destination network does, unless the provider says otherwise.

On landing : activate the eSIM line as your data line, let the phone search for the local network, and wait a minute or two. The first connection is sometimes slow.

When you get back : delete or deactivate the profile, and switch data back to your main line. An expired eSIM profile left active can stop the phone from finding its usual network.

🏝️ Island by island: what to expect on the ground

Having data doesn't guarantee having signal. Here is what you need to know about the destinations outside the European zone that we cover.

On small islands in general, the rule is simple: coverage follows the people. A village has signal, an isolated beach often doesn't. Download offline maps before heading out on a hike — that's as true on Groix as on Santo Antão.

⚠️ The Cuba case: the exception that breaks the rule

Cuba deserves a paragraph of its own, because it is the destination where the usual advice doesn't work. The national operator ETECSA holds a monopoly and has not signed the roaming agreements that travel eSIMs rely on. The result: most foreign eSIMs there are either unavailable or so slow they become unusable, with speeds measured at around 1 Mbit/s and frequent drop-outs, when a connection is established at all.

On the ground, the solution that works is still the tourist SIM card sold by ETECSA, at the airport or in shops, at around $3 a day for one gigabyte, with much faster speeds. Hotel wifi and Nauta cards complete the picture.

In other words: for Cuba, plan differently, and above all don't count on your phone the way you would elsewhere. Warn your loved ones that you will only be reachable intermittently, and download everything you need before you leave.

📡 Wifi, local SIM, hotspot: the alternatives

Hotel wifi is enough for many travellers, especially on resort stays. It falls short as soon as you move around: finding your way in town, calling a taxi or checking a ferry timetable are needs out in the field, not in your room.

A local SIM card is often still the cheapest option and the only one that gives you a real local number — handy for booking a restaurant or reaching a rental company. On the downside: queues on arrival, ID to show, main card to remove, and sometimes a tedious registration procedure. It's the right choice for a long stay, rarely for a week.

A pocket wifi device has the advantage of connecting several devices and several travellers. You have to rent it, carry it, charge it and return it. For a group on the same trip, the maths can work; on your own, almost never.

❓ Frequently asked questions

🔗 Further reading

• The travel guideAll our practical guides for planning an island trip
• Islands with good weather in winterWhere to go when the days get shorter
• When to go to the Canary Islands?Weather month by month and island by island
• Tourist offices and transportOfficial websites and connections, destination by destination

The Dem-Tukki editorial team

We cover 170 islands in five languages, from the Glénan to the Maldives, with one rule: check before we claim.

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