One of those travel/fold-up umbrellas cuz it almost always rains on at least one island for at least an hour or so.
Also- since you can't use your cell phone on the ship (the roaming charges would be outrageous!), to communicate with family members traveling with you, bring walkie talkies.
Lastly, I'm gonna bring little things to dress-up the towel animals (and YES, take pics-lol)
I go on the Destiny in about 2 1/2 weeks- YAY!
**The clothes pins were a great idea, I never thought of that!