No passport. No exchange rate. No customs line.

TSA began full REAL ID enforcement on May 7, 2025, and it applies to every domestic boarding, including SJU to the mainland and back. A standard, non-compliant state driver's license is no longer enough on its own. Bring one of the acceptable IDs on TSA's list: a REAL ID-compliant license or ID card, marked with a star; a US passport or passport card; a DHS Trusted Traveler card such as Global Entry, NEXUS, or SENTRI; a permanent resident card; or a US military ID.

If you arrive at the checkpoint without any acceptable ID, TSA's fallback is the ConfirmID identity-verification process, which per TSA's own REAL ID page carries a $45 fee, takes extra time, and does not guarantee you fly if your identity cannot be verified. The practical advice has not changed: check your license for the star before you book anything, and if it does not have one, bring your passport even though the destination does not require it.

Green-card holders: a permanent resident card is on TSA's acceptable-ID list, so you can fly to Puerto Rico and back on the green card alone, exactly as you would fly New York to Miami. No passport, no re-entry paperwork, because you never leave the United States.

Visitors from abroad: there is no separate Puerto Rico visa. You need whatever authorization you would need to enter the US at all, a visa or an ESTA approval under the Visa Waiver Program. Once you have been admitted to the US, the flight to San Juan is a domestic leg, and TSA accepts a foreign government-issued passport as checkpoint ID. The one thing to keep straight is your overall US admission period: time in Puerto Rico counts as time in the US, nothing more.

The moment your itinerary leaves US territory. Puerto Rico sits within an easy hop of foreign islands, and a side trip to the Dominican Republic, the British Virgin Islands, or the Dutch and French islands further south is international travel with a passport requirement like any other. If there is any chance your trip grows a foreign leg, bring the passport even though Puerto Rico itself never asks for it.

The useful exception: the US Virgin Islands. St. Thomas, St. John, and St. Croix are also US territory, so the popular Puerto Rico plus USVI combination stays passport-free the whole way, by air or by sea.

Flying into San Juan to board a ship is the same domestic trip as any other Puerto Rico visit: REAL ID rules, no passport. What happens next depends on the sailing. On a closed-loop cruise, one that departs and returns to the same US port, CBP's Western Hemisphere Travel Initiative rules let US citizens sail with a birth certificate plus a government-issued photo ID instead of a passport.

Two honest caveats before you sail on a birth certificate. First, individual foreign islands on the itinerary can still require a passport regardless of what CBP accepts back home; the cruise line's documentation page for your specific sailing is the authority. Second, if anything goes wrong mid-cruise, an illness, a missed departure, the only way home from a foreign port is by air, and that requires a passport. That is why nearly every line recommends one even when the rules technically do not. If your cruise is a Puerto Rico port stop rather than a homeport departure, our cruise port guide covers how to spend the day.

Because Puerto Rico is US territory, the small logistics stay familiar. USPS delivers here at domestic rates, so shipping a box of souvenirs home or forwarding something you forgot costs the same as mailing between states. Power outlets are the same 120-volt US plugs, no adapter needed. Amazon and the other big mainland retailers ship to Puerto Rico addresses, which matters more for longer stays.

The one clock quirk: Puerto Rico is on Atlantic Standard Time year-round and does not observe daylight saving. In the US summer that makes it the same time as the East Coast; in winter it runs one hour ahead. Worth knowing for booking flights and calling home, and that is the whole list of surprises.

There is no immigration or customs process flying between the mainland and Puerto Rico. There is, however, a federal USDA agricultural inspection every passenger clears before checking bags for a flight out of San Juan back to the mainland. Inspectors screen for items that could carry pests or disease to the continental US: fresh fruit and vegetables, plants and cuttings, soil, and certain animal products.

Some things pass with inspection, per USDA's own allowed list: roasted or green coffee beans travel without restriction, and items like bananas, coconuts, and papayas are generally allowed once checked. Mangoes and soursop are the classic confiscations. Rum, packaged snacks, and anything commercially sealed are not an issue. The process itself is quick, each terminal has its own screening point before the check-in counters, but it is one more line, so build in a little extra airport time rather than cutting a standard domestic-flight schedule close.