You must be extremely cautious when bringing seashells back from St. Maarten, as many are protected by international law. Specifically, it is illegal to transport Queen Conch shells or certain types of coral out of Sint Maarten without a special permit, as they fall under the CITES (Convention on International Trade in Endangered Species) treaty. In recent years, customs at Princess Juliana International Airport have collaborated with nature foundations to seize hundreds of kilos of illegally collected shells. Even if you purchase a shell from a vendor, it may be confiscated if you don't have the proper documentation. For small, common beach shells, U.S. and European customs generally allow them if they are entirely clean and free of sand, soil, or organic matter (like algae or pieces of the animal), but they must still be declared. To avoid heavy fines or the loss of your souvenirs in 2026, the best peer-to-peer advice is to "take only pictures" and avoid large, ornate shells that are likely part of a protected local ecosystem.