Because Long Island is a destination for true explorers, sturdy hiking shoes or sneakers are a must for visiting the Columbus Monument or navigating the rocky cliffs on the Atlantic side. Pack high-quality snorkel gear to fully enjoy the clear visibility at Dean’s Blue Hole and various shallow reefs. Since the island is sparsely populated, a reusable water bottle and portable snacks are essential for day trips, as shops can be miles apart. You will also want to bring biodegradable insect repellent for the evening "no-see-ums" and reef-safe sunscreen for the intense tropical sun. A rented car is the best way to see the island’s full 80-mile length, so ensure you have your driver's license and extra cash, as many local gas stations and small eateries do not accept credit cards.