Ontario CA to San Francisco (ONT → SFO). We are tracking 21 fares on this route.
Cheapest tracked fare $28 · typical price $98 · you save about $70 (72%)
Cheapest fares we're tracking
Airline
Departs
Stops
Price
Frontier Airlines
2026-09-17
Direct
$28
Frontier Airlines
2026-09-21
Direct
$28
Frontier Airlines
2026-09-24
Direct
$28
Frontier Airlines
2026-09-28
Direct
$28
Frontier Airlines
2026-10-22
Direct
$28
Frontier Airlines
2026-10-19
Direct
$31
Frontier Airlines
2026-10-12
Direct
$46
Frontier Airlines
2026-10-30
Direct
$46
Frontier Airlines
2026-09-15
1 stop
$59
United Airlines
2026-09-09
Direct
$70
Frontier Airlines
2026-09-16
1 stop
$71
Frontier Airlines
2026-09-22
1 stop
$71
Frontier Airlines
2026-09-30
1 stop
$72
Frontier Airlines
2026-09-04
Direct
$74
Frontier Airlines
2026-09-26
1 stop
$76
Frontier Airlines
2026-10-09
Direct
$76
Southwest Airlines
2026-10-03
1 stop
$77
United Airlines
2026-12-24
Direct
$78
United Airlines
2026-10-20
Direct
$79
Frontier Airlines
2026-10-31
1 stop
$79
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 San Francisco get?
The cheapest fare we have tracked on this route is $28, compared with a typical $98 for a trip of this distance.
Is it cheaper to fly to San Francisco 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 San Francisco 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.