Every year, cruisers come home to eye-watering phone bills for data they didn’t know they used. The culprit is almost always the same: the ship’s satellite network, billed by their home carrier at maritime rates. The good news is that avoiding it takes about two minutes of settings changes before you sail. Here’s exactly what to do.
Why this happens
Out at sea there’s no land mobile tower, so your phone latches onto the only signal available: the ship’s onboard cell, which relays to a satellite. Your carrier sees that as international maritime roaming — one of the most expensive things a phone can do. Background app refreshes, photo backups and a single video can quietly run up hundreds of dollars before you’ve noticed.
The fix on iPhone
- Open Settings → Cellular (or Mobile Service).
- Tap your primary line, then turn Data Roaming OFF.
- For total peace of mind, also turn the line’s Cellular Data / Turn On This Line off, or put the whole phone in Airplane Mode and re-enable just WiFi.
- Turn off Settings → [your name] → iCloud → iCloud Photos → Cellular, and disable background app refresh on cellular, so nothing sneaks data through.
The fix on Android
- Open Settings → Network & internet → SIMs (wording varies by maker).
- Select your primary SIM and turn Roaming OFF.
- Optionally enable Airplane Mode, then switch WiFi back on.
- Under Settings → Network & internet → Data Saver, and in Auto-sync, restrict background data so apps don’t update over a roaming connection.
But I still want to be online — what then?
Turning off roaming doesn’t mean going dark. It only stops your home carrier from billing you. You stay connected far more cheaply with travel eSIMs:
- In port: a cheap local or regional eSIM gives you fast land data for a few dollars. Airalo and Saily are great value; Holafly if you want unlimited.
- At sea: GigSky is the only eSIM that connects mid-ocean, at a flat data rate that’s a tiny fraction of per-MB carrier roaming.
Crucially, install and set these up at home over WiFi before you board — activation needs an internet connection you won’t have cheaply once you’re aboard.
Watch out for “cruise packages” from your carrier
Many home carriers sell a “cruise” or “at-sea” roaming add-on for around $10–$15 a day. They work, but they’re usually the most expensive way to stay connected, because they still ride the same satellite link. A GigSky at-sea pass plus cheap port eSIMs almost always costs less over a full sailing — we run the comparison in our WiFi vs eSIM cost breakdown.
A quick pre-cruise checklist
- ☐ Data roaming OFF on your home line.
- ☐ (Optional) Airplane Mode on for the voyage, WiFi back on manually.
- ☐ Background photo/cloud backup over cellular disabled.
- ☐ A port eSIM installed and ready.
- ☐ A GigSky at-sea pass installed if you want sailing-day data.
- ☐ Everything bought and set up before you board, on home WiFi.
Do those six things and a surprise roaming bill becomes essentially impossible.
For the bigger picture on what your phone does at sea versus in port, read our at-sea vs in-port explainer or head to the cruise eSIM hub.