Ontario CA to Seattle (ONT → SEA). We are tracking 21 fares on this route.
Cheapest tracked fare $46 · typical price $161 · you save about $115 (71%)
Cheapest fares we're tracking
Airline
Departs
Stops
Price
Frontier Airlines
2026-09-08
Direct
$46
Frontier Airlines
2026-09-25
Direct
$47
Frontier Airlines
2026-09-10
Direct
$49
Frontier Airlines
2026-09-09
Direct
$49
Frontier Airlines
2026-10-05
Direct
$53
Frontier Airlines
2026-09-26
Direct
$58
Frontier Airlines
2026-10-03
Direct
$58
Frontier Airlines
2026-09-13
Direct
$61
Frontier Airlines
2026-09-24
Direct
$62
Frontier Airlines
2026-10-04
Direct
$63
Frontier Airlines
2026-09-27
Direct
$63
Frontier Airlines
2026-09-19
Direct
$67
Frontier Airlines
2026-09-23
Direct
$74
Frontier Airlines
2026-10-31
Direct
$74
Frontier Airlines
2026-09-06
Direct
$76
Frontier Airlines
2026-10-07
Direct
$83
Frontier Airlines
2026-11-09
Direct
$99
Frontier Airlines
2026-10-11
Direct
$100
Frontier Airlines
2026-09-20
Direct
$116
Southwest Airlines
2026-10-10
1 stop
$117
Could you save more?
The airport you were going to fly from is often not the cheapest one. Compare every airport in a region against each other, or check whether a multi-day stopover beats the direct fare.
How cheap can flights from Ontario CA to Seattle get?
The cheapest fare we have tracked on this route is $46, compared with a typical $161 for a trip of this distance.
Is it cheaper to fly to Seattle from a different airport?
Often, yes. Fares out of secondary airports are frequently cheaper than the obvious hub, but they are the ones most likely to be missing from a normal search. Our reverse search compares every airport in a region against each other so the cheaper departure point is not hidden.
Could a stopover make Ontario CA to Seattle cheaper?
Sometimes. On thin long-haul routes a two-leg trip with a multi-day stopover can beat the direct fare, and occasionally a direct fare is not sold at all. Our detour search prices those routings against the direct flight.