Luggage and bags:
Unless you want to pack just carry-ons, which is possible on Isla, because you don't need much to wear, I highly recommend getting big light sports bag and packing a couple of comfy pillows from home. Sometimes beds in Mexico can be on the hard side, but no complaints if you have good pillows!
Clothing/Shoes/Weather Gear: Take mostly swimsuits, shorts and t-shirts, hat, and something a little nicer for the evening. But it is very casual on Isla. Take a jacket or sweater on Isla in case ir gets windy, which can make it a little chilly some evenings. Shoes: flip flops or beach sandals, running shoes for longer walks, and a pair of dressier sandals for ladies.
Toiletries and Medical Supplies: Toiletries and medical supplies are on the expensive side so take them with you, including lots of sunscreen and aloe lotion. But there is a great pharmacy where you can get what you need if you forget anything.
Photo Equipment: Take a disposable underwater camera for pictures of all the great fishes on the reef when you go snorkelling.
Camping/Beach/Outdoor Gear: Along with our pillows in the sports bag, we take our snorkelling stuff: fins, mask and snorkel. Also a couple of really lightweight floatie rings for the pool or ocean. You can also inflate the rings slightly upon your return trip for cushioning breakables.
Miscellaneous: Leave the expensive jewellry at home.
Toiletries and Medical Supplies:
Suntan lotion is a must for us norteamericanos.
Camping/Beach/Outdoor Gear: A towel for the beach at Playa Norte. Bikini tops are optional, and the west end of the beach (left as you face the ocean) is swimsuit optional.
Miscellaneous: Snorkeling equipment can be brought or rented on the island.
Luggage and bags:
Try to use just carry-ons...you'll get to the ferry quicker if you don't have to wait for your big bags.
Toiletries and Medical Supplies: Lots of SPF! It's really easy to over do it.
Photo Equipment: I was wishing I had brought an underwater camera. The reefs are beautiful and very alive.