Alaska Airlines Flights from Ontario to Seattle

Lowest fares from Ontario to Seattle

Aug 2026
From$189*
Seen: 22 hours ago
Flight Type One Way|Saver
Sep 2026
From$134*
Seen: 22 hours ago
Flight Type One Way|Saver
Oct 2026
From$134*
Seen: 22 hours ago
Flight Type One Way|Saver
cmp-daily-histogram-bars-legend-min-price-aria-label $154
cmp-daily-histogram-bars-legend-max-price-aria-label $484
Displaying fares for August-2026
  • ONT–SEA, Aug 9, 2026: From $484
    09

    Su

    AUG

  • ONT–SEA, Aug 10, 2026: From $409
    10

    Mo

  • ONT–SEA, Aug 11, 2026: From $409
    11

    Tu

  • ONT–SEA, Aug 12, 2026: From $409
    12

    We

  • ONT–SEA, Aug 13, 2026: From $399
    13

    Th

  • ONT–SEA, Aug 14, 2026: From $324
    14

    Fr

  • ONT–SEA, Aug 15, 2026: From $324
    15

    Sa

  • ONT–SEA, Aug 16, 2026: From $324
    16

    Su

  • ONT–SEA, Aug 17, 2026: From $324
    17

    Mo

  • ONT–SEA, Aug 18, 2026: From $324
    18

    Tu

  • ONT–SEA, Aug 19, 2026: From $324
    19

    We

  • ONT–SEA, Aug 20, 2026: From $324
    20

    Th

  • ONT–SEA, Aug 21, 2026: From $244
    21

    Fr

  • ONT–SEA, Aug 22, 2026: From $244
    22

    Sa

  • ONT–SEA, Aug 23, 2026: From $244
    23

    Su

  • ONT–SEA, Aug 24, 2026: From $244
    24

    Mo

  • ONT–SEA, Aug 25, 2026: From $244
    25

    Tu

  • ONT–SEA, Aug 26, 2026: From $244
    26

    We

  • ONT–SEA, Aug 27, 2026: From $244
    27

    Th

  • ONT–SEA, Aug 28, 2026: From $244
    28

    Fr

  • ONT–SEA, Aug 29, 2026: From $189
    29

    Sa

  • ONT–SEA, Aug 30, 2026: From $189
    30

    Su

  • ONT–SEA, Aug 31, 2026: From $189
    31

    Mo

  • ONT–SEA, Sep 1, 2026: From $189
    01

    Tu

    SEP

  • ONT–SEA, Sep 2, 2026: From $189
    02

    We

  • ONT–SEA, Sep 3, 2026: From $209
    03

    Th

  • ONT–SEA, Sep 4, 2026: From $209
    04

    Fr

  • ONT–SEA, Sep 5, 2026: From $209
    05

    Sa

  • ONT–SEA, Sep 6, 2026: From $189
    06

    Su

  • ONT–SEA, Sep 7, 2026: From $210
    07

    Mo

  • ONT–SEA, Sep 8, 2026: From $154
    08

    Tu

    • Range$154-$484

    *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: 22 hours ago

    Ontario (ONT)Seattle (SEA)One-way
    |
    Saver    		Depart: Dec 5, 2026

    From

    $134

    Seen: 22 hours ago

    Ontario (ONT)Seattle (SEA)One-way
    |
    Saver    		Depart: Dec 8, 2026

    From

    $134

    Seen: 22 hours ago

    Ontario (ONT)Seattle (SEA)One-way
    |
    Saver    		Depart: Dec 15, 2026

    From

    $134

    Seen: 22 hours ago

    Ontario (ONT)Seattle (SEA)One-way
    |
    Saver    		Depart: Sep 26, 2026

    From

    $134

    Seen: 22 hours ago

    Ontario (ONT)Seattle (SEA)One-way
    |
    Saver    		Depart: Oct 6, 2026

    From

    $134

    Seen: 22 hours ago

    Ontario (ONT)Seattle (SEA)One-way
    |
    Saver    		Depart: Nov 18, 2026

    From

    $134

    Seen: 22 hours ago

    Ontario (ONT)Seattle (SEA)One-way
    |
    Saver    		Depart: Dec 9, 2026

    From

    $134

    Seen: 22 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.

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