San Salvador is remote, so "self-sufficiency" is the theme for your packing list. Bring high-quality snorkel or dive gear, as the island’s vertical walls are its main attraction and rentals can be limited outside of the few major resorts. Sturdy hiking shoes are essential for climbing the rocky trail to the Dixon Hill Lighthouse or exploring the limestone ruins of old plantations. Because the island is exposed to the open Atlantic, the sun is exceptionally strong; pack long-sleeved rash guards, a wide-brimmed hat, and reef-safe sunscreen. You should also bring a basic first-aid kit and any necessary medications, as pharmacies are scarce. Finally, carry plenty of cash, as there are very few ATMs on the island, and many local guesthouses and small cafes do not accept credit cards.