How early should I get to ONT?
Ontario International Airport, Ontario, CA · Checked Oct 26, 2026
The short answer
ONT officials recommend arriving 2 hours before a domestic flight (June 2024 release)
ONT officials recommend arriving 3 hours before an international flight (June 2024 release)
Those are blanket rules. Your real number depends on your terminal, the time of day, traffic from your door, and whether you have PreCheck or a bag. Leave By works out your exact leave time.
Source: prnewswire.com
Security lines at ONT
This research found no published ONT peak times. In TSA's hourly screening counts for Sep 13-19, 2026, ONT was busiest from 4am to 6am, peaking 5-6am; screening began in the 3am hour. There was a second rise from 9am to noon, peaking 11am-noon. Afternoons were quieter, and there was a smaller evening rise from 8pm to 11pm. Friday and Thursday were the busiest days that week, followed by Monday and Sunday; Tuesday, Saturday and Wednesday were the quietest.
Busiest times: 4:00-6:00am (peak 5:00-6:00am), 9:00am-12:00pm (peak 11:00am-12:00pm), Fridays and Thursdays, then Mondays and Sundays (TSA counts, week of Sep 13, 2026).
Nationally, TSA checkpoints are busiest from 5 to 7 AM local time. See TSA's hourly numbers and the busiest days to fly.
TSA PreCheck: Both checkpoints have PreCheck screening. ONT says the Terminal 2 checkpoint has a lane mainly for PreCheck, and that a similar lane would open soon at Terminal 4 (August 2026). CLEAR lists PreCheck hours at both terminals as the same as its CLEAR lane hours. ONT says PreCheck use doubled in two years to 26% of departing passengers. CLEAR offers PreCheck enrollment and renewal in both terminals, with no appointment needed.
CLEAR: Available at this airport (see terminals below for which checkpoints).
Touchless ID: ONT is not on Southwest's list of TSA PreCheck Touchless ID airports, and it was not in The Points Guy's May 2026 table of Touchless ID airports. This research found no Touchless ID at ONT.
Terminals and checkpoints
Terminal 2
Alaska, Avianca, China Airlines, Delta, Frontier, United, Volaris
- CLEAR's enrollment spot is on the ground floor at the main entrance, across from the Alaska ticket counter
- The evening rush from 8pm to 11pm in TSA's counts was larger here than in Terminal 4
Terminal 4
American, JetBlue, Southwest, Starlux
- CLEAR's enrollment spot is on the ground floor at the main entrance, across from the Southwest ticket counter
- JetBlue lists no curbside check-in and no self-service kiosks at ONT
Between terminals: Terminals 2 and 4 are separate buildings, each with its own checkpoint. AirportMapHQ (March 2026) says there is no connection after security. Before security, a covered walkway links the two terminals, and a free shuttle runs between Terminal 2, Terminal 4 and the Rental Car Center.
Terminals are not connected after security. Go to the right terminal the first time.
Getting to ONT
Rideshare and taxi: Uber says all pickups are on the inner curb at Terminals 2 and 4 and at the international terminal. ONT says it offers curbside access for rideshare.
Transit: ONT Connect (Omnitrans Route 380) runs nonstop between the airport and Rancho Cucamonga Metrolink station (San Bernardino Line) seven days a week, timed to meet trains. The City of Rancho Cucamonga says it leaves hourly. Fares match Omnitrans' regular fares, and Metrolink pass holders get one free transfer. Omnitrans Route 61 links the airport with the Ontario Amtrak station, Pomona and Fontana.
Driving and parking: Use I-10 (San Bernardino Freeway); I-15 and SR-60 are also nearby. Daily rates in ONT's FY2026-27 schedule (updated June 2026): Lots 2 and 4 $30, or $35 for premium spaces immediately in front; Lot 3 $25; Lots 1, 5 and 6 $20; valet $40. ONT says rates can change, and booking parking ahead earns a discount.
Construction and changes in 2026
- The Terminal 4 checkpoint is getting one more screening lane and a new secure exit corridor. ONT said in July and August 2026 that they would open soon; this research could not confirm whether they have opened.
Checking a bag
Southwest: check bags at least 45 minutes before a domestic flight's scheduled departure (60 minutes for international), and check in at least 30 minutes before a domestic flight. American and United: check in and check bags 45 minutes before most domestic flights; Alaska: check in at least 50 minutes before a domestic flight (AP, May 2025). Delta: bags 45 minutes before domestic departure, check-in 30 minutes without bags. Frontier: check-in and bag drop close 60 minutes before departure.
ONT tips first-timers miss
- Check your terminal: Southwest, American, JetBlue and Starlux use Terminal 4; Alaska, Delta, United, Frontier, Volaris, Avianca and China Airlines use Terminal 2. The terminals are not connected after security.
- ONT's rush starts very early. In TSA's counts for mid-September 2026, screening began in the 3am hour and peaked 5-6am.
- CLEAR lanes close in the late afternoon or early evening: by 4:30-5pm in Terminal 2 and 6-7pm in Terminal 4
- Flying Frontier? Check-in and bag drop close 60 minutes before departure, earlier than most airlines.
- Book parking ahead for a discount. Lots 1, 5 and 6 are the cheapest, at $20 a day.
Leaving for ONT?
Pick your flight and where you're starting. Leave By checks live traffic, security lines and your terminal, and tells you the minute to walk out the door.
Free. No account.
Questions travelers ask
How early should I get to Ontario airport (ONT)?
ONT officials recommend 2 hours before a domestic flight and 3 hours before an international flight. Security is busiest from 4am to 6am.
Which terminal is Southwest at ONT?
Terminal 4. American, JetBlue and Starlux also use Terminal 4. Alaska, Delta, United, Frontier, Volaris, Avianca and China Airlines use Terminal 2.
Are ONT's Terminal 2 and Terminal 4 connected?
Not after security. Each terminal has its own checkpoint. Before security, a covered walkway and a free shuttle link the two.
Does ONT have TSA PreCheck and CLEAR?
Yes, at both terminals. CLEAR lanes open at 4am and close at 4:30-5pm in Terminal 2 and 6-7pm in Terminal 4. CLEAR also offers PreCheck enrollment in both terminals.
Can I take the train to ONT?
Yes, with a bus connection. Take Metrolink's San Bernardino Line to Rancho Cucamonga station, then the ONT Connect bus (Omnitrans Route 380), which runs nonstop to the airport and is timed to meet trains.
Sources
- ONT - July 4th travel forecast with arrival advice (PR Newswire, Jun 26, 2024)
- ONT - Next-generation passenger screening at Terminal 2; Terminal 4 work (PR Newswire, Jul 27, 2026)
- ONT - More travelers choosing TSA PreCheck as airport expands screening (PR Newswire via Webull, Aug 3, 2026)
- ONT - Summer 2026 forecast (parking, rideshare) (PR Newswire)
- ONT - Passenger traffic through September 2026 (PR Newswire, Oct 22, 2026)
- ONT - FY2026-27 Airport System Rates and Charges (parking rates, updated June 2026)
- ONT - July 2026 airport statistics (airlines serving ONT)
- CLEAR - Ontario International Airport locations & hours
- JetBlue - Ontario, CA airport information (Terminal 4, checkpoint hours)
- Visit Anaheim - Ontario International Airport (airlines by terminal)
- AirportMapHQ - Ontario Airport terminal guide (updated Mar 29, 2026)
- Future Travel Experience - ONT expands security checkpoints (Aug 2026)
- Uber - Ontario airport pickups
- City of Rancho Cucamonga - Cucamonga Station and ONT Connect
- Wikipedia - Ontario International Airport
- Southwest - TSA PreCheck Touchless ID (participating airports)
- The Points Guy - TSA PreCheck Touchless ID airports (May 2026)
- Southwest - When to arrive for your flight (check-in and bag deadlines)
- Delta - Check-In Times at U.S. Airports
- Frontier - Flight timing (check-in and bag drop cutoff)
- AP via MyNorthwest - United narrows check-in window; airline comparison (May 27, 2025)
- TSA throughput data, September 13-19, 2026
Airport conditions change. Always follow your airline's check-in and bag-drop deadlines.