1-856-513-6369

Cheap Flights from Seattle to Ontario (SEA to ONT) from $114.00

Compare the cheapest Seattle (SEA) to Ontario (ONT) fares found by our live flight search, then book online or over the phone with our travel experts.

📞 Call 1-856-513-6369
Adults
12+
1
Children
2–11
0
Infants
Under 2
0
Cabin
🏷️
Save up to 40% with unpublished phone fares
Consolidator deals on selected Seattle → Ontario flights that do not appear in online search results. The live fares below are bookable right now — or call to check for an unpublished fare on your dates.
📞 1-856-513-6369

One-way fares Seattle → Ontario

showing indicative fares · loading live prices…
Frontier
Frontier CHEAPEST
SEA → ONT · Economy
lowest fare seen on this route
$190.59
$114.35
Select
Alaska Airlines
Alaska Airlines
SEA → ONT · Economy
lowest fare seen on this route
$322.20
$193.32
Select
Delta Air Lines
Delta Air Lines
SEA → ONT · Economy
lowest fare seen on this route
$342.40
$205.44
Select
United Airlines
United Airlines
SEA → ONT · Economy
lowest fare seen on this route
$383.70
$230.22
Select
See all flights & times → Prices per adult, one way, incl. taxes & fees. Availability changes constantly.
📞 Call for phone-only fares ✈ See flights

Cheapest fares from Seattle to Ontario

Lowest fare found per airline on the SEA → ONT route, with our discounted phone-deal price.

AirlineCabin Found fareOur discounted fare Fare found on
Frontier Frontier Economy $190.59 $114.35 Sep 12, 2026 Book
Alaska Airlines Alaska Airlines Economy $322.20 $193.32 Sep 12, 2026 Book
Delta Air Lines Delta Air Lines Economy $342.40 $205.44 Sep 12, 2026 Book
United Airlines United Airlines Economy $383.70 $230.22 Sep 12, 2026 Book

Discounted fares are negotiated phone deals from our vendor network and may not appear in online search results — call 1-856-513-6369 to lock one in. Fares were found on the dates shown, are per person in USD, and change with availability.

Related routes

↩ Ontario to Seattle Seattle to Akron Seattle to Anchorage Seattle to Austin Seattle to Burbank Seattle to Calgary Seattle to Cancún Atlanta to Ontario Augusta to Ontario Austin to Ontario Baton Rouge to Ontario Blountville to Ontario Boise to Ontario All routes →

Why book with Globitude Travels

💸 Transparent pricing
The fare you see is all-inclusive — taxes and fees shown before you pay, never after.
🤝 Real travel experts
Every booking is reviewed by our team, and phone-only vendor deals can beat any online price.
🎧 24/7 human support
Before, during and after your trip — changes, cancellations and special requests handled by people.
🔒 Secure checkout
Encrypted payment, verified confirmation emails, and your PNR delivered as soon as the airline issues it.

Globitude Travels is an independent travel agency — call 1-856-513-6369 or use the search above to compare live fares on this route. See our terms, privacy policy, refund policy and service fees for full details, or contact us any time.

Page updated September 20, 2026 · fare data refreshed automatically from live flight searches.