Sometimes it is hard to pack for a place or climate that is new. When packing to go to the tropics there are some items that you don't want to forget.
1. Appropriate Identification: With tighter security these days it simply makes sense to carry a passport and photo ID. Also be sure to have identification for your children traveling with you.
2. Contraceptives: Well... If you think you will be getting down and dirty on your trip you should bring contraceptives.
3. Appropriate Clothing: Yes the tropics are warm but if a sudden storm rolls in it can get quite cool, fast. Always bring good shoes, pants and even a light jacket.
I find it is better to pack lightly, You never know when you will need to carry your luggage for a distance. 3 or 4 full changes of cloths will often be enough.
4. Sunscreen: SPF 30 minimum. Any less and you stand to get burned. A sunscreen should also contain either zinc oxide or titanium oxide.
Before leaving on your trip it is a good idea to spend some time in a tanning bed. This can give you a good base to withstand the intense sun near the equator.
5. Medication: Obviously bring any prescription medication but you should also think about Aspirin, Pepto Bismal and other pharmacy items.
Be sure to carry any medicine in the original package and carry copies of your prescription as well.
6. Guide Book: A guide book to the area that you are visiting can come in real handy. Besides showing you the attractions in the area it will also have important phone numbers in case of an emergency.
7. Cash: Having a credit card and travelers cheques with you is a must. Also carry enough American cash for 2 days of emergency living. You never know when a storm will knock out the power.
8. Snorkel: If you have any plans to go snorkeling you may want to bring you own snorkel and mask, or at least a snorkel. Rentals are shared by many people. If you are packing light a snorkel takes up almost no space.