We have a SIM from Chippie and our phone works fine all over the island, both in Saint-Martin FWI and Sint Maarten. You can purchase a Chippie SIM from a U.S. based outfit or buy one on the island at their office or very likely at the phone store located at the Bush Road Carrefour market. Now that many newer phones use eSIMs, I would assume that Chippie can supply those, too.