Flights from Ontario (ONT) to Seattle (SEA) on Alaska Airlines

Lowest fares from Ontario to Seattle

Oct 2026
From$264*
Seen: 18 hours ago
Flight Type One Way|Saver
Nov 2026
From$134*
Seen: 18 hours ago
Flight Type One Way|Saver
Dec 2026
From$134*
Seen: 18 hours ago
Flight Type One Way|Saver
cmp-daily-histogram-bars-legend-min-price-aria-label $134
cmp-daily-histogram-bars-legend-max-price-aria-label $303
Displaying fares for October-2026
  • ONT–SEA, Oct 16, 2026: From $303
    16

    Fr

    OCT

  • ONT–SEA, Oct 17, 2026: From $274
    17

    Sa

  • ONT–SEA, Oct 18, 2026: From $303
    18

    Su

  • ONT–SEA, Oct 19, 2026: From $303
    19

    Mo

  • ONT–SEA, Oct 20, 2026: From $274
    20

    Tu

  • ONT–SEA, Oct 21, 2026: From $274
    21

    We

  • ONT–SEA, Oct 22, 2026: From $303
    22

    Th

  • ONT–SEA, Oct 23, 2026: From $303
    23

    Fr

  • ONT–SEA, Oct 24, 2026: From $274
    24

    Sa

  • ONT–SEA, Oct 25, 2026: From $303
    25

    Su

  • ONT–SEA, Oct 26, 2026: From $303
    26

    Mo

  • ONT–SEA, Oct 27, 2026: From $274
    27

    Tu

  • ONT–SEA, Oct 28, 2026: From $264
    28

    We

  • ONT–SEA, Oct 29, 2026: From $264
    29

    Th

  • ONT–SEA, Oct 30, 2026: From $274
    30

    Fr

  • ONT–SEA, Oct 31, 2026: From $274
    31

    Sa

  • ONT–SEA, Nov 1, 2026: From $294
    01

    Su

    NOV

  • ONT–SEA, Nov 2, 2026: From $254
    02

    Mo

  • ONT–SEA, Nov 3, 2026: From $254
    03

    Tu

  • ONT–SEA, Nov 4, 2026: From $199
    04

    We

  • ONT–SEA, Nov 5, 2026: From $239
    05

    Th

  • ONT–SEA, Nov 6, 2026: From $239
    06

    Fr

  • ONT–SEA, Nov 7, 2026: From $239
    07

    Sa

  • ONT–SEA, Nov 8, 2026: From $239
    08

    Su

  • ONT–SEA, Nov 9, 2026: From $199
    09

    Mo

  • ONT–SEA, Nov 10, 2026: From $199
    10

    Tu

  • ONT–SEA, Nov 11, 2026: From $219
    11

    We

  • ONT–SEA, Nov 12, 2026: From $239
    12

    Th

  • ONT–SEA, Nov 13, 2026: From $179
    13

    Fr

  • ONT–SEA, Nov 14, 2026: From $134
    14

    Sa

  • ONT–SEA, Nov 15, 2026: From $179
    15

    Su

    • Range$134-$303

    *Displayed prices have been available within the past 24 hours and may not be available at the time of booking. Fares listed may be Saver fares, which is our most restrictive fare option and subject to additional restrictions. For roundtrip journeys, the price displayed—available within the past 24 hours—is the aggregate of the lowest available fare each way. Additional baggage charges and fees for optional products and services may apply. Other terms and conditions may apply.

    One-way low-fare flights Ontario to Seattle.*

    $
    keyboard_arrow_down
    One-way low-fare flights Ontario to Seattle.*
    From
    To
    Fare Type
    Dates
    Price
    Ontario (ONT)Seattle (SEA)One-way
    |
    Saver    		Depart: Nov 14, 2026

    From

    $134

    Seen: 18 hours ago

    Ontario (ONT)Seattle (SEA)One-way
    |
    Saver    		Depart: Jan 12, 2027

    From

    $134

    Seen: 18 hours ago

    Ontario (ONT)Seattle (SEA)One-way
    |
    Saver    		Depart: Jan 16, 2027

    From

    $134

    Seen: 18 hours ago

    Ontario (ONT)Seattle (SEA)One-way
    |
    Saver    		Depart: Jan 19, 2027

    From

    $134

    Seen: 18 hours ago

    Ontario (ONT)Seattle (SEA)One-way
    |
    Saver    		Depart: Jan 20, 2027

    From

    $134

    Seen: 18 hours ago

    Ontario (ONT)Seattle (SEA)One-way
    |
    Saver    		Depart: Feb 23, 2027

    From

    $134

    Seen: 18 hours ago

    Ontario (ONT)Seattle (SEA)One-way
    |
    Saver    		Depart: Feb 24, 2027

    From

    $134

    Seen: 18 hours ago

    Ontario (ONT)Seattle (SEA)One-way
    |
    Saver    		Depart: Mar 3, 2027

    From

    $134

    Seen: 18 hours ago

    *Displayed prices have been available within the past 24 hours and may not be available at the time of booking. Fares listed may be Saver fares, which is our most restrictive fare option and subject to additional restrictions. For roundtrip journeys, the price displayed—available within the past 24 hours—is the aggregate of the lowest available fare each way. Additional baggage charges and fees for optional products and services may apply. Other terms and conditions may apply.

    Frequently Asked Questions on flights from Ontario (ONT) to Seattle (SEA)

    When is the best time to book a flight from Ontario to Seattle?

    Want to find the lowest fares by day and time flying from Ontario to Seattle on Alaska Airlines or Hawaiian Airlines? Check out our flight search widget.

    Can I earn points on my flight to Seattle?

    Yes, with Atmosâ„¢ Rewards you can earn points on flights to 1000+ destinations worldwide through the growing network of Alaska and Hawaiian Airlines. Not an Atmosâ„¢ Rewards member yet? Learn more and join today.

    Can I rent a car when I arrive at Seattle/Tacoma International Airport?

    Yes, you can rent a car at Seattle/Tacoma International Airport. Check availability and book now

    Where can I find the status of my flight to Seattle?

    You can check the status of your upcoming Alaska Airlines flight on our flight schedule page.

    Where can I find answers to questions about flying with Alaska Airlines?

    Visit the Alaska Airlines Help Center to quickly browse our help pages by category to find the information you need.

    Can I change or cancel my Alaska Airlines flight to Seattle?

    Yes, you can review, modify, or cancel a reservation from our Manage Your Reservation tool. You can learn more about our policy for changing or cancelling a reservation here. 

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