How to get Wi-Fi on a ship?
On a ship, you can connect in two different ways: by using the Wi-Fi offered by the cruise line on board, which travels via satellite and almost always costs extra, or by using your cell phone's mobile data when you are near the coast or in port, where a local eSIM picks up the country's network just like on land.
The most common confusion is treating both things as if they were the same. They are not. Ship Wi-Fi is a closed network that the cruise line installs for the entire ship. Mobile data is the direct connection between your cell phone and a country's cell towers, with no involvement from the ship. Understanding this difference is what prevents you from overpaying or losing signal when you least expect it, and that's exactly what this guide is about.
Whether you're traveling on a cruise, ferry, or private boat, the rules change depending on how far you are from the coast. Let's break it down.
How do ships have Wi-Fi?
A ship in the middle of the sea doesn't have fiber optic cables or cell towers nearby. To get internet, most cruise ships and large vessels use an antenna that points to a satellite (the technology is called VSAT) or, on newer ships, to a constellation of low-orbit satellites like Starlink Maritime. This antenna receives the signal and distributes it throughout the ship via an internal Wi-Fi network, similar to that of a hotel.
The problem is that this satellite bandwidth is shared by thousands of passengers and the entire crew simultaneously, and it travels much farther than a normal cell signal. That's why a ship's Wi-Fi is usually slower than your home Wi-Fi and, in most cases, costs extra beyond the cruise ticket. The more modern the ship (and the newer its satellite system), the better the speed tends to be, but the difference between cruise lines and between ships from the same cruise line can be significant.
Ship Wi-Fi vs. mobile data: two different things
Think of ship Wi-Fi as a hotel network: it covers the building (the ship), the operator of the building (the cruise line) pays for it, and it ceases to exist as soon as you disembark. Mobile data with an eSIM works differently: it's your cell phone communicating directly with a country's phone network, so it stays with you, not the ship, and continues to work as soon as you set foot on land without needing to sign up for anything new.
| Aspect | Ship Wi-Fi (satellite) | Mobile data / eSIM |
|---|---|---|
| Who offers it | The cruise line, for the entire ship | A telecommunications operator in the country you are in |
| Where it works | Anywhere on the route, as long as the system is active | Only where there is cell tower coverage (coast and port, not at sea) |
| How it's paid for | Separate from the ticket, daily, by data package, or included in some cabins | With your eSIM plan, active as long as the purchased plan lasts |
| How stable it is | Depends on the weather, how many passengers use it simultaneously, and the ship's satellite system | As stable as the country's network in that coastal area |
| Stays with you when you disembark | No, it stays on the ship | Yes, it remains active in the country you visit |
Neither is generally "better": they are tools for different moments. Ship Wi-Fi makes sense at sea, when there are no cell towers nearby. Mobile data makes sense in port and in stretches near the coast, where you don't need to pay the cruise line to check a map or send a message.
When does an eSIM work on a ship (and when does it not)?
An eSIM works on a ship exactly like your cell phone works anywhere else: if there's a cell tower within range, you have signal; if there isn't, you don't. Near the coast (in port, departing or arriving, or sailing close to the shore) it's normal to pick up the country's network as if you were on land. At sea, far from any coast, no SIM card in the world (physical or eSIM) will find a signal, because there simply aren't any towers to connect to.
Here it's worth clarifying something that almost no one explains and that can save you a big scare: some cruise ships and ferries install their own mini cell network on board, distinct from the ship's Wi-Fi, which automatically connects your cell phone via satellite when it detects that there are no terrestrial towers nearby. This network appears on your cell phone as if it were a normal company, and if your SIM is not configured to block it, it can generate very high roaming charges without you having intentionally used either the ship's Wi-Fi or a local eSIM. The way to avoid this is simple: put your cell phone in airplane mode (or disable mobile data) as soon as you set sail, and only activate it when you want to use the ship's Wi-Fi or when the captain announces that you are already near port.
If you want to understand in depth the difference between this and traditional roaming you would use with your usual operator, the guide on eSIM vs. roaming explains it in more detail.
How much does it cost to get Wi-Fi on a cruise?
There's no single figure, as each cruise line sets its own packages, and prices vary depending on speed, number of devices, and trip duration. What you can expect, however, is the same pattern across almost all of them: a basic package for messaging and email, an intermediate one for social media and normal browsing, and a more expensive one for video calls or streaming. Some cruise lines charge per connected device, others per entire cabin, and some already include basic Wi-Fi in higher cabin categories.
Before purchasing any package, check the website or app of your cruise line directly for options and prices for your specific ship and itinerary: they change from season to season and from ship to ship, even within the same company.
How to get internet on a cruise without overpaying?
The most practical strategy combines the two tools from the previous section, each where it performs best:
- Download what you'll need offline before sailing: offline maps of each port, the cruise itinerary, music or series, and the addresses of places you plan to visit.
- Keep your phone in airplane mode while at sea, unless you decide to pay for the ship's Wi-Fi for something specific.
- Activate a local or regional eSIM for port days, so you can use maps, translate a menu, or request a ride without relying on the ship's Wi-Fi or the hotel's network where you stay before or after the cruise.
- Disable automatic app updates and cloud backups: these are the most common ways to consume data (from the ship's Wi-Fi or your plan) without realizing it.
- Use the ship's Wi-Fi only for essentials at sea (messages, email) and save heavy usage (video, social media with lots of content) for when you're in port with local data.
Ship Wi-Fi connects you to the ship. The eSIM connects you to the country. Confusing one with the other is the most common way to overpay or lose signal at the worst possible moment.
Real-life example: a Caribbean cruise
To make it clearer, let's look at a specific case. Someone departs from Miami on a seven-day Western Caribbean cruise, with stops in Cozumel (Mexico), Roatán (Honduras), and Nassau (Bahamas), and two full days of sailing at sea between ports.
| Time of travel | Are there cell towers nearby? | Recommended connection |
|---|---|---|
| Leaving Miami (first hours) | Yes, while the ship is near the Florida coast | Normal mobile data, no need for ship Wi-Fi |
| Full day at sea | No, no terrestrial towers reach that distance | Airplane mode, or ship Wi-Fi if you need something specific |
| Stop in Cozumel, Mexico | Yes, local Mexican network available | Active eSIM for Mexico: maps, translation, requesting a ride |
| Stop in Roatán, Honduras | Yes, local Honduran network available | Active eSIM for Honduras (or a regional plan covering Central America) |
| Stop in Nassau, Bahamas | Yes, local Bahamian network available | Active eSIM for Bahamas |
| Return to Miami | Yes, as soon as it approaches the coast | Normal mobile data again |
With an eSIM plan that covers the route's destinations, this person arrives at each port and their cell phone connects automatically, without needing to find a local SIM card or rely on the cruise line's hotel Wi-Fi. The two days at sea are spent in airplane mode, without spending anything, and they only use the ship's Wi-Fi if they need to send an urgent email.
Ferries and short trips: a different case
Not all boats are week-long cruises. A ferry between Buenos Aires and Colonia del Sacramento, one between Baja California and the Mexican Pacific, or a catamaran between Caribbean islands, almost always sail close to the coast, so it's common to have cell signal throughout the trip, with no real stretches at sea.
In these cases, there's almost never a need to pay for onboard Wi-Fi: having an active eSIM for the departure country or the arrival country (depending on which best covers the route) is enough to be connected from the first minute. It's the same principle as on a cruise, except here almost the entire journey counts as "near the coast."
How to get your eSIM ready before sailing
Installing an eSIM requires an internet connection, so the worst time to do it is already on the boat. The correct order is this:
- Confirm that your cell phone is eSIM compatible. Most recent models are, but it's worth checking first: here's the list of eSIM compatible phones.
- Choose a plan that covers the countries on your itinerary, not just the departure country. If your cruise calls at several countries, a regional plan is usually better than buying one for each stop.
- Install the eSIM with stable Wi-Fi, ideally at home or at your hotel before boarding the ship. The complete step-by-step guide is in how to install an eSIM.
- Keep your usual physical SIM as a backup for traditional calls or text messages, without activating its data, to avoid the automatic roaming we mentioned earlier.
- Check the plan map to see which of your stops are covered and which ones you'll need to rely on the ship's or port's Wi-Fi.
You can view all multi-country plans in the international eSIM collection and choose the one that best fits your ship's route.
Frequently Asked Questions
How to get Wi-Fi on a ship?
By purchasing the cruise line's Wi-Fi package for use at sea, or by using your cell phone's mobile data (with a local eSIM) when the ship is near the coast or in port. It's almost always best to combine the two depending on the timing of your trip.
How do ships have Wi-Fi?
Because they have an antenna that connects to a satellite (VSAT or constellations like Starlink Maritime) and distributes that signal throughout the ship via an internal Wi-Fi network, similar to a hotel's.
How much does it cost to get Wi-Fi on a cruise?
It depends on the cruise line, the speed of the package, whether it's charged per device or per cabin, and the season. There is no fixed price: you have to check it directly on the cruise line's website or app for your ship and itinerary.
How to get internet on a cruise without overpaying?
By downloading maps and offline content before sailing, using airplane mode at sea, activating a local or regional eSIM for port days, and saving the ship's Wi-Fi for essentials only.
Does an eSIM work at sea?
No, because there are no cell towers at sea to connect to. No SIM, physical or eSIM, has signal there. The eSIM will work again as soon as the ship approaches the coast or arrives in port.
What is "maritime roaming" and why can it be expensive?
It is a cellular network that some ships install on board and that automatically connects your cell phone via satellite when there is no terrestrial signal nearby. Since it appears as a normal network, if your mobile data is activated without you realizing it, it can generate high charges. This is avoided by putting your cell phone in airplane mode when sailing.
Can I use the same eSIM in multiple countries during a cruise?
Yes, if you choose a regional or multi-country plan that covers the destinations on your itinerary, your cell phone will automatically connect to the local network at each stop without you having to change plans at each port.
Is an eSIM useful for a short ferry trip?
Yes. On short trips close to the coast, like many ferries, there is usually cell signal throughout the crossing, so an active eSIM from the departure or arrival country is usually sufficient without needing to pay for onboard Wi-Fi.
Conclusion
Ship Wi-Fi and mobile data with an eSIM solve different problems: one keeps you connected at sea, for an additional fee, and the other connects you as on land as soon as you're near the coast, without relying on the cruise line. Most boat trips (cruises with several stops, ferries, catamarans) spend more time near the coast than at sea, so a well-chosen eSIM covers a good part of the journey without spending on the ship's most expensive package.
If your next trip includes a ship, the first practical step is to check which countries your itinerary touches and activate an eSIM that covers them before sailing. You can review the available plans by destination in PuraSIM's international eSIM collection, with activation in approximately 1 minute, more than 200 destinations available, and 24/7 support in all languages via email and WhatsApp if anything is unclear before you set sail. And if you want to review other questions before your trip, the definitive guide to eSIM for travel is a good next step.
