Puerto Rico — Visa & Airports

Puerto Rico is US territory: US citizens fly in domestically with no passport, and everyone else needs exactly what they would for the mainland United States — ESTA under the Visa Waiver Program for UK/EU and most Western passports (90 days), a B-2 visa otherwise, with Canadians visa-exempt. There is no separate Puerto Rican immigration; you clear US CBP at your first port of entry, and flights from the mainland arrive as domestic flights with no checks.

Luis Muñoz Marín International (SJU) sits in Carolina, immediately east of the Isla Verde hotel strip — 10-25 minutes to most San Juan lodging. It is the Caribbean's biggest hub, with heavy nonstop traffic to the US East Coast, plus Madrid and regional islands. Aguadilla (BQN) and Ponce (PSE) take some US budget-carrier flights for the west and south.