I've been to Phuket in Thailand (ummm... that's pronounced "Pooket" for those of you who were wondering!) and had a wonderful time swimming, riding elephants, kayakking, etc.
We went to a floating village where the toilets were literally holes cut in the floor but they were manageable. The floor was soaked but I'm hoping that was water since there was a hose there to wash things down with once you were done! The hardest part was stopping the bottom of my jeans from getting wet from the (what I hope was) water on the floor.
Take at least twice as many supplies with you as you would normally use in the same time period. For some reason I always go through more bags while away on holidays. Don't drink the water - your hotel will usually provide a pitcher of safe drinking water for you in your room each day and don't eat from any dodgy roadside vendors.
I haven't been SCUBA diving but know many ostomates who have - one ostomate friend is even a SCUBA instructor!
Pack some supplies with you in your hand luggage in case your main luggage ends up in Antarctica! That way you'll at least be covered until you can get your things back (but pre-cut everything - don't take scissors with you in your hand luggage. If you use tape, pre-cut the tape, stick it onto a plastic zip lock baggy so all you have to do is peel it off again to use).
The best advice I can give is to have fun!
I have had an ileostomy for 32 years now due to UC.
Moderator of the Ostomy Forum
I'm not a complete idiot - some parts of me are missing!