Does an eSIM work on a cruise? Ports yes, sea no
A land eSIM works in cruise ports and on shore excursions, and it does not work at sea. Port cities sit on the ordinary land networks that your plan lists as coverage. The ship runs its own maritime network from the moment she leaves the quay. No land plan covers that network, so the ship's Wi-Fi is your way online at sea.
Ports yes, sea no
Your eSIM works wherever the ship is tied up, and it goes quiet once she sails. Shore excursions run on the same land networks as the port itself. The maritime network at sea is a separate thing, and no land plan lists it as coverage. That gap shows up as an empty signal bar on the eSIM line, not as an error. Nothing has failed on the phone or on the profile when you see it happen. Plan your ports as the connected part of the day, and treat sea days as Wi-Fi days.
Which plan covers a multi-country cruise
One global plan covers an itinerary that calls at several countries. The Discover eSIM lists 202 countries on one shared allowance, checked 5 September 2026. That allowance follows you from port to port with no change of profile. Its days run as calendar days from your first connection in the first port you reach. Sea days in between still count against that run. A fortnight afloat therefore needs a plan of 30 days rather than one of five. The 10 GB, 30-day plan was $45.99 on 5 September 2026. A two-port taster cruise fits one of the smaller plans of a few days instead.
The switches at sea and in port
The roaming switches point in opposite directions at sea and in port. At sea, keep data roaming off on both lines, the physical SIM and the eSIM alike. That keeps either line from attaching to the maritime network the ship runs for itself. In port, turn data roaming back on for the eSIM line and for that line only. It then registers on the local land network exactly as it would on any other trip. Leave the physical SIM's data roaming off for the whole voyage. The same pair of switches applies at every port of call, not only at the first.
Your number, the ship's Wi-Fi and WhatsApp
Your own number stays on the physical SIM for the whole voyage, at sea and ashore. That line goes on carrying your calls and texts wherever the ship happens to be. WhatsApp keeps the number registered to that SIM, whatever line is carrying the data. At sea it runs over the ship's Wi-Fi, with no data plan involved at any point. Ashore it runs on the eSIM's data, like everything else on the phone. The number in the tray never changes, only the network underneath it.
Before you sail
Do the whole setup at home, while you still have Wi-Fi. Install the eSIM there, because the install screen needs a working connection to finish. Let it activate on your first connection in the first port of the itinerary. That keeps the day count from starting on a sea day you cannot use. Turn data roaming off on both lines before the ship leaves that first port behind. Android phones use the APN value 'wbdata' on this profile, and it loads by itself. Store the ship's Wi-Fi login on the first evening aboard.
Before you go
- Install the eSIM at home over Wi-Fi, and activate it on your first connection in port.
- Turn data roaming off on both lines before the ship leaves each port.
- Turn data roaming back on for the eSIM line once you are ashore at the next port.
- Use the ship's Wi-Fi at sea, and keep the physical SIM for calls and texts.