Since attire is casual, the usual uniform being a pair of shorts and (sometimes) a shirt, and the climate is warm and dry, you don't need to bring much.
To bring: the usual beach wears along with something for dining and dancing in the evenings. A light wind jacket is an option but not necessary.
Most important items being: SPF 30+, sun hat, sun glasses, long sleeved lycra, harness, and some insect repellent. You WILL NOT need a wetsuit. Some other items you may consider bringing are a pair of gloves and booties for windsurfing.
There are a number of supermarkets in town which carry all the basics (and we mean basic), such as sunscreen. However, items like these can come at a higher cost and a lower quality, so better to bring them with you.
SUGGESTED PACKING LIST:
SPF 50 (lots!)
Flip flops or sandals
Long lightweight pants
Long-sleeve lightweight shirt
Sunglasses + one spare pair (just in case)
Any personal prescriptions or medicine
Spare contacts or glasses
Gloves and boots (if you wear them)
It is best to have local currency before getting to Jeri. Funds can be exchanged or withdrawn from bank machines at the airport or in Fortaleza. Try to get small bills, since it's sometimes tricky getting change.
Contact your travel agent or Brazilian consulate to find out if a visa is required.
SUGGESTED LIST OF THINGS TO LEAVE BACK HOME:
In case you bring it, it will be forgotten on the first day here. So, you might as well leave it at home.