Actually, the rules that are posted where you get on the boat state that you cannot bring your own food or drink to the island. I don't believe they enforce that too strictly. I've seen someone denied access as they were carrying a big cooler. We've carried a small softside cooler that holds about 8 cans with no problem. The drinks and food at the restaurant on the island is not that expensive. They have servers that go around taking orders and will deliver it to you at the beach.