Connecting at O'Hare: what time you land changes everything

Last checked 30 September 2026

At O'Hare, a genuine dual hub for American and United, three of the four terminals are an easy walk from each other behind security. The fourth, Terminal 5, depends entirely on what time your flight lands or leaves.

At a glance

• Terminals 1, 2 and 3: connected to each other by walkways without leaving security, whichever combination you're using.
• Terminal 5 (Delta's entire operation, plus international arrivals): the one that needs planning. Between 11:30 a.m. and 9:30 p.m., a bus for same-day connecting passengers keeps you behind security the whole way. Outside those hours, the only way there or back is a train that's on the outside of security, meaning you'll go through a security check again at the other end.
• Arriving from abroad, connecting onward: passport control at Terminal 5: half of passengers were through within 13 minutes; one passenger in ten waited about 37 minutes or more (GateCast estimate from US Customs and Border Protection wait data, Sep 2025 to Sep 2026), though O'Hare's own site says it is rare for the whole immigration and customs process to take more than two hours; you'll then recheck bags before your next flight. A few flights from Canada and Ireland clear US border checks before departure and skip straight to baggage claim.

Three terminals connected, one apart

Terminal 1 is United's home at O'Hare, the airport's largest terminal, split into two concourses. Terminal 2 holds Air Canada, Alaska and JetBlue, plus some United Express services. Terminal 3 is American's Chicago hub. All three are joined by walkways on the secure side of the airport, so moving between any of them is just a walk — no train ride, no new checkpoint.

Terminal 5 is different, and it now holds all of Delta's O'Hare flights — domestic and international — since Delta moved there entirely in October 2022. It has no walkway to the other three, and how you reach it depends on the clock. From 11:30 a.m. to 9:30 p.m., a dedicated bus for same-day connecting passengers links Terminal 5 with Terminal 1 and with Terminal 3, staying behind security throughout. The airport's own page names only those two routes, so check with the airport or your airline before assuming one from Terminal 2. Outside that window, there's no route that stays behind security: you'd take O'Hare's other train, the Airport Transit System, which runs around the clock but sits outside security, meaning a security check again once you get where you're going.

Arriving internationally

Follow these steps in order. International arrivals come in through Terminal 5.

1. If you're on one of the flights from a handful of Canadian airports or Ireland that clear US border checks before departure: you go straight to domestic baggage claim, with no further steps.
2. Everyone else: clear passport control and customs at Terminal 5. At passport control alone, half of passengers were through within 13 minutes; one passenger in ten waited about 37 minutes or more (GateCast estimate from US Customs and Border Protection wait data, Sep 2025 to Sep 2026); O'Hare's own site says it is rare for the whole immigration and customs process to take more than two hours.
3. If you're checked all the way through to your final destination: drop your bag at the recheck counters right outside the customs area, whatever airline you're on.
4. If you're not checked through and flying onward with United or American: recheck your bag right there too.
5. If you're not checked through and flying another airline: carry your bag out of Terminal 5 yourself and recheck it with your airline before your next flight.

Tips

• Flying Delta at O'Hare? You're in Terminal 5, for both domestic and international flights, since October 2022 — don't assume Terminal 2 from an older guide or a well-meaning friend's memory.
• Landing or departing through Terminal 5 outside the 11:30 a.m.–9:30 p.m. window is the one thing at O'Hare worth real extra time for — it's a different, slower route than the daytime one.
• If you're not sure whether your connection to or from Terminal 5 falls inside the bus's hours, check the clock before you check the map — it matters more here than which terminal letter you're at.
• Not flying United or American and arriving internationally with a connection that isn't checked all the way through? Budget extra time to carry your own bag out of Terminal 5 and recheck it yourself.

Checked 30 September 2026. Terminals, schedules and procedures change, so confirm with the airport and your airline before you travel.

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