On a cruise or a ferry: what a travel eSIM can and cannot do
There are no masts mid-ocean; what your phone finds is the ship's own network, billed separately.
Quick answer
- Travel plans cover land networks, not the satellite networks that ships operate.
- Switch data roaming off, or use airplane mode, once you leave shore to avoid charges you did not intend.
- Plan the heavy usage for port days, when the plan works normally.
As a ship leaves the coast the phone drops the land network and may attach to the vessel's own. The name on screen often looks like an ordinary operator, which is why people do not realise they have moved onto an entirely different, far more expensive system.
Before you board
- Download maps, tickets and documents for offline use
- Turn data roaming off on every profile before departure
- Set network selection to manual so the phone does not attach to the ship's network on its own
- If you must be online, buy the ship's own package and read its terms first
Port days are when the plan earns its keep
Alongside in port, the phone reattaches to that country's land network and your plan works as usual. If the itinerary calls at several countries, check that each one appears on the covered list.
FAQ
Can I use airplane mode with the ship's Wi-Fi?+
Yes, and it is the safest approach: airplane mode on, Wi-Fi on separately, and the phone never attaches to the ship's cellular network.
What about short cross-strait ferries?+
Close-to-shore routes often keep intermittent land signal. Expect gaps rather than a steady connection.