Airplane mode is still useful
Ship Wi-Fi and cellular roaming are separate. Put the phone in airplane mode, then manually enable Wi-Fi if you want to avoid accidental maritime cellular charges.
One-device plans require device switching
A plan that permits one device at a time may allow you to log out and move the connection, but simultaneous use requires more access.
Do not promise office-grade reliability
Modern satellite systems have improved cruise internet, but a ship remains a moving shared network. Critical meetings deserve a contingency plan.
Download before boarding
Offline maps, entertainment, documents and authentication backups reduce your dependence on the ship connection.
Turn the advice into a trip plan
Write down the decision that affects your booking or port day, the deadline for making it, and the information that could still change. Cruise planning gets easier when permanent preferences are separated from live operational details.