Terminal 2
The larger of the two main terminals, with a six-lane security checkpoint that includes a lane for TSA PreCheck travelers. Aspire Lounge is here, along with the nursing room past security near Gate 206.
Ontario International Airport (ONT) terminal guide
Ontario, California KONT #53 US airport by passengers
How ONT is laid out and how to move between buildings.
Terminals at ONT
Terminal 4
The second main terminal, with its own checkpoint. The airport is adding a dedicated PreCheck lane here, and Aspire Lounge is also available. The nursing room is past security near Gate 408.
International Arrivals Terminal
The federal inspection facility for international arrivals. Lot 1 is the paid lot for international arrivals travelers, and shuttle service is not scheduled from this lot.
Moving between terminals
Terminal 2 and Terminal 4 are separate buildings, each with its own checkpoint. Check which terminal your flight uses before you park. The Ontario-USO lounge in the historic Terminal 1 has a free shuttle from Terminals 2 and 4.
Reviewed October 9, 2026. Confirm details on the official airport website. Spotted a change?