Cheap flights from Ontario to Seattle

Cheapest current fares: $124 in August 2026, 1,540 km direct flight in ~1h 49m.

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Live fares · ONT → SEA

Cheapest month-by-month fares

Lowest available fare per calendar month from Ontario (ONT) to Seattle (SEA). Refreshed daily.

Ontario (ONT) → Seattle (SEA)

  1. August 2026 $124

Frequently asked questions

  • What is the cheapest month to fly from Ontario to Seattle?

    Based on current 6-month forward fare data, August 2026 is the cheapest month to fly from Ontario (ONT) to Seattle (SEA), with fares starting from $124.

  • What is the lowest current fare from ONT to SEA?

    The lowest currently-listed fare from Ontario (ONT) to Seattle (SEA) is $124 on 2026-08-27.

  • How long is the flight from Ontario to Seattle?

    Direct flights from ONT to SEA cover approximately 1,540 km (957 miles), with an estimated flight time of 1h 49m. Operating airlines: AS, DL, F9.

Related guides for this route

Sibling pages — full route detail, airport overviews, visa context, per-airline routes.

Full route page: ONT → SEA Cheapest month to fly to Seattle All flights from Ontario All flights to Seattle Flights to USA Visa-free with USA passport AS routes DL routes F9 routes