It is almost unthinkable for us, but the internet is limited at many super beautiful diving locations. Especially when you consider that many ships sail far from land and therefore simply do not have an internet connection available. Some ships do offer Wifi, but that does not mean that you always have an internet connection and to be honest, that is so nice. Get away from the world for a while, really socialize with other divers, go on an adventure without Facebook. Still, it is useful to be able to send a message home to let those who stay at home know that you are doing well. Therefore, when you arrive on board, ask for a WiFi connection, possibly a hotspot, so that you can send that one message before the boat sets out.
If the ship now has WiFi, their options are often limited. So turn off all roaming, don’t upload anything to the cloud and don’t try to stream anything to limit your data usage. If you have an action camera that puts everything on your phone or tablet with an app, don’t worry, WiFi also works without internet, but then you must already have the app on your phone. So download all your things before you travel, or take an adapter with you so that you can have your SD card read directly by your tablet or phone.