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Connections at IAH: the honest numbers
The indicative minimum international-to-international connection at Houston George Bush is 90 minutes on a single booking with bags checked through. On separate tickets, add roughly 90 minutes: you'll collect bags, recheck them, and re-clear security — and no airline is obliged to help if the first leg runs late.
Transfer specifics
- The United States does not operate sterile international transit areas. Every passenger arriving from abroad clears Customs and Border Protection even when they are only connecting, which means you are formally entering the country for a two-hour layover. Visa Waiver Program nationals — the UK, Australia, Japan, most of Europe — need an approved ESTA, and when the application asks whether the US is your final destination you answer no. Everyone else needs a C-1 transit visa, or an existing valid B visitor visa. There is no version of this where you simply stay airside and skip it.
- The practical sequence catches people out too: after CBP you exit the secure area, collect your checked bags, drop them at the recheck belt and clear TSA again. Even a connection with no terminal change involves handling your luggage. Budget properly — two hours is comfortable, ninety minutes is tight, and anything under that is a gamble on the CBP hall being quiet.
- IAH has five terminals and two separate train systems, and confusing them is the classic Houston mistake. The Skyway runs above ground and inside security, connecting Terminals A, B, C and D/E every two minutes, with the full run from Terminal A to D/E taking about four and a quarter minutes. If you are connecting and already airside, this is the one you want.
- The Subway runs underground and outside security, connecting the same terminals plus the Airport Marriott every three minutes — but only from roughly 3:30am to 12:30am, closing overnight. Boarding it by accident means re-clearing TSA on the other end. Terminals D and E handle international flights and share a single Skyway station, so an international-to-international connection at IAH usually involves no train ride at all once you are back through security.
Leaving IAH during a layover
You clear immigration on arrival whatever your plans, so leaving is a question of time rather than permission. Downtown Houston is roughly 35 to 45 minutes away depending on traffic, which is manageable but not quick, and you will clear TSA again on return. Six hours is the sensible floor for going into the city; below that the terminal is the better call. The city is about 40 minutes away one-way; as a rule of thumb you want 6+ hours before exiting is worth the queues, and you should be back through security 90 minutes before boarding.
Worth your hours in Houston
- The Museum District clusters the Museum of Fine Arts, the Houston Museum of Natural Science and the Menil Collection within a walkable area, and the Menil is free — the most content per hour available on a Houston layover.
- Space Center Houston is the trip people actually want, but be honest about distance: it is well south of downtown and closer to an hour each way from the airport, so it needs a genuinely long connection rather than a six-hour one.
- Buffalo Bayou Park runs along the water at the edge of downtown and works as a low-commitment stop if the weather is reasonable, with the downtown skyline and the bat colony under Waugh Bridge at dusk.
Staying airside instead
- Terminals D and E are the international side and carry the better food and lounge options. Because they share a Skyway station and connect directly, an international connection at IAH is usually a short walk rather than a train ride.
- The Skyway means the airside estate across all five terminals is open to you between flights, which is a real advantage on a long connection — but remember it stops being useful the moment you go landside for bag recheck.
- The Airport Marriott sits on the Subway line inside the airport grounds, which makes it unusually easy to reach for a misconnection, though reaching it means being landside.
Sleeping, showers and lounges at IAH
Sleep: The Houston Airport Marriott sits within the airport grounds on the Subway line, which makes it the obvious answer to an overnight connection — and since you clear immigration on arrival anyway, using it carries no extra visa complication. Note that the Subway stops running around 12:30am, so a very late arrival means a taxi across the airport rather than the train. Airport hotels & sleep pods
Showers: Showers are tied to lounge access rather than being available to walk-up passengers, so they depend on your ticket or status. United's Polaris lounge in Terminal E is the best of them but requires an eligible international business-class ticket.
Lounges: Terminal E holds United's Polaris lounge for long-haul business passengers, with United Clubs across the terminals and Priority Pass options available. The Skyway makes a lounge in another terminal genuinely reachable between flights, provided you stay airside. Priority Pass membership (frequent flyers)
Overnight reality: IAH operates around the clock but the Subway closes from roughly 12:30am to 3:30am, which strands landside terminal transfers overnight. If you have an overnight connection, either stay airside in Terminals D or E, or commit to the Airport Marriott early enough to reach it while the Subway is still running.
IAH layover FAQ
Do I need a visa or ESTA to connect through Houston?
Yes. US airports have no sterile international transit, so every international arrival clears CBP even on a short connection. Visa Waiver Program nationals need an approved ESTA and should answer no when asked whether the US is their final destination; everyone else needs a C-1 transit visa or a valid B visitor visa. Staying airside is not an option that exists in the United States.
What is the difference between the Skyway and the Subway at IAH?
The Skyway runs above ground inside security, connecting Terminals A, B, C and D/E every two minutes, about four minutes end to end. The Subway runs underground outside security, connecting the same terminals plus the Airport Marriott every three minutes, roughly 3:30am to 12:30am. If you are connecting and already through security, take the Skyway — boarding the Subway means clearing TSA again.
Which terminal is international at Houston Bush?
Terminals D and E handle international flights and share a Skyway station, so they connect directly. That makes an international-to-international connection relatively simple at IAH once you are back through security — the time cost is CBP and the bag recheck, not the terminal change.
How long do I need for an international connection at IAH?
Around two hours is comfortable and ninety minutes is tight. The sequence is CBP, baggage claim, recheck, TSA, then the Skyway if you need it. Because Terminals D and E adjoin, the walking is rarely the problem — the immigration hall is.
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Minimum connection times are indicative and vary by airline, terminal pair and season; visa notes are simplified general guidance, not immigration advice. Facts on this page were last verified on 2026-08-05. If anything has changed, tell us and we'll fix it fast.