Expect the infamous "gypy" tummy and then if you don't get it you will be pleased
Expect to be shattered by 9pm and 1 beer every night.
Expect to do nothing more energetic than fall off a boat, or roll over in the sun.
Expect to get bored of the food after day 3 when it all starts to weirdly taste the same.
Expect to only need a tiny torch for the best night dives as the whole point is not to scare off or fry the things that like to live in the dark.
But most of all....
Expect to have a brilliant time! It really shouldn't disappoint in any way.