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

Lowest fares from Ontario to Seattle

Nov 2026
From$177*
Seen: 18 hours ago
Flight Type One Way|Saver
Dec 2026
From$134*
Seen: 18 hours ago
Flight Type One Way|Saver
Jan 2027
From$129*
Seen: 18 hours ago
Flight Type One Way|Saver
cmp-daily-histogram-bars-legend-min-price-aria-label $139
cmp-daily-histogram-bars-legend-max-price-aria-label $348
Displaying fares for November-2026
  • ONT–SEA, Nov 11, 2026: From $279
    11

    We

    NOV

  • ONT–SEA, Nov 12, 2026: From $308
    12

    Th

  • ONT–SEA, Nov 13, 2026: From $308
    13

    Fr

  • ONT–SEA, Nov 14, 2026: From $279
    14

    Sa

  • ONT–SEA, Nov 15, 2026: From $308
    15

    Su

  • ONT–SEA, Nov 16, 2026: From $308
    16

    Mo

  • ONT–SEA, Nov 17, 2026: From $279
    17

    Tu

  • ONT–SEA, Nov 18, 2026: From $279
    18

    We

  • ONT–SEA, Nov 19, 2026: From $308
    19

    Th

  • ONT–SEA, Nov 20, 2026: From $308
    20

    Fr

  • ONT–SEA, Nov 21, 2026: From $279
    21

    Sa

  • ONT–SEA, Nov 22, 2026: From $308
    22

    Su

  • ONT–SEA, Nov 23, 2026: From $269
    23

    Mo

  • ONT–SEA, Nov 24, 2026: From $269
    24

    Tu

  • ONT–SEA, Nov 25, 2026: From $269
    25

    We

  • ONT–SEA, Nov 26, 2026: From $269
    26

    Th

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

    Fr

  • ONT–SEA, Nov 28, 2026: From $299
    28

    Sa

  • ONT–SEA, Nov 29, 2026: From $348
    29

    Su

  • ONT–SEA, Nov 30, 2026: From $177
    30

    Mo

  • ONT–SEA, Dec 1, 2026: From $145
    01

    Tu

    DEC

  • ONT–SEA, Dec 2, 2026: From $145
    02

    We

  • ONT–SEA, Dec 3, 2026: From $157
    03

    Th

  • ONT–SEA, Dec 4, 2026: From $157
    04

    Fr

  • ONT–SEA, Dec 5, 2026: From $145
    05

    Sa

  • ONT–SEA, Dec 6, 2026: From $177
    06

    Su

  • ONT–SEA, Dec 7, 2026: From $177
    07

    Mo

  • ONT–SEA, Dec 8, 2026: From $145
    08

    Tu

  • ONT–SEA, Dec 9, 2026: From $139
    09

    We

  • ONT–SEA, Dec 10, 2026: From $177
    10

    Th

    • Range$139-$348

    *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: Jan 6, 2027

    From

    $129

    Seen: 18 hours ago

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

    From

    $129

    Seen: 18 hours ago

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

    From

    $129

    Seen: 18 hours ago

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

    From

    $129

    Seen: 18 hours ago

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

    From

    $129

    Seen: 18 hours ago

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

    From

    $129

    Seen: 18 hours ago

    Ontario (ONT)Seattle (SEA)One-way
    |
    Saver    		Depart: Feb 27, 2027

    From

    $129

    Seen: 18 hours ago

    Ontario (ONT)Seattle (SEA)One-way
    |
    Saver    		Depart: Mar 9, 2027

    From

    $129

    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. 

    Looking for more? See other routes