Flights from Ontario/LA, CA to Seattle, WA

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Best Deals on Flights From Ontario/LA, CA (ONT) to Seattle, WA (SEA)

Aug 2026
from$149*
Last seen: 4 hours ago
One-way/Economy
Sep 2026
from$46*
Last seen: 7 hours ago
One-way/Economy
Oct 2026
from$46*
Last seen: 3 hours ago
One-way/Economy
cmp-daily-histogram-bars-legend-min-price-aria-label $63
cmp-daily-histogram-bars-legend-max-price-aria-label $185
Displaying fares for August-2026
  • ONT–SEA: cmp-view-offers-disclaimer. Find Offers
    15

    Sat

    AUG

  • ONT–SEA: cmp-view-offers-disclaimer. Find Offers
    16

    Sun

  • ONT–SEA, Aug 17, 2026: from $178
    17

    Mon

  • ONT–SEA, Aug 18, 2026: from $178
    18

    Tue

  • ONT–SEA, Aug 19, 2026: from $178
    19

    Wed

  • ONT–SEA, Aug 20, 2026: from $185
    20

    Thu

  • ONT–SEA, Aug 21, 2026: from $169
    21

    Fri

  • ONT–SEA, Aug 22, 2026: from $175
    22

    Sat

  • ONT–SEA, Aug 23, 2026: from $169
    23

    Sun

  • ONT–SEA, Aug 24, 2026: from $169
    24

    Mon

  • ONT–SEA, Aug 25, 2026: from $163
    25

    Tue

  • ONT–SEA, Aug 26, 2026: from $169
    26

    Wed

  • ONT–SEA: cmp-view-offers-disclaimer. Find Offers
    27

    Thu

  • ONT–SEA, Aug 28, 2026: from $149
    28

    Fri

  • ONT–SEA: cmp-view-offers-disclaimer. Find Offers
    29

    Sat

  • ONT–SEA, Aug 30, 2026: from $155
    30

    Sun

  • ONT–SEA, Aug 31, 2026: from $149
    31

    Mon

  • ONT–SEA, Sep 1, 2026: from $126
    01

    Tue

    SEP

  • ONT–SEA, Sep 2, 2026: from $136
    02

    Wed

  • ONT–SEA, Sep 3, 2026: from $149
    03

    Thu

  • ONT–SEA, Sep 4, 2026: from $142
    04

    Fri

  • ONT–SEA, Sep 5, 2026: from $83
    05

    Sat

  • ONT–SEA, Sep 6, 2026: from $108
    06

    Sun

  • ONT–SEA, Sep 7, 2026: from $128
    07

    Mon

  • ONT–SEA, Sep 8, 2026: from $93
    08

    Tue

  • ONT–SEA, Sep 9, 2026: from $83
    09

    Wed

  • ONT–SEA, Sep 10, 2026: from $108
    10

    Thu

  • ONT–SEA, Sep 11, 2026: from $108
    11

    Fri

  • ONT–SEA, Sep 12, 2026: from $63
    12

    Sat

  • ONT–SEA, Sep 13, 2026: from $88
    13

    Sun

  • ONT–SEA, Sep 14, 2026: from $72
    14

    Mon

    • Range$63-$185

    *Prices found by others in the previous 48 hours for round-trip flights. Prices shown may also require membership in our travel club, Discount Den.

    Flights Deals from Ontario/LA, CA to Seattle, WA on Frontier

    $
    Flights Deals from Ontario/LA, CA to Seattle, WA on Frontier
    From
    To
    Ontario/LA, CA (ONT)Seattle, WA (SEA)One-way
    /
    Discount Den Basic Fare    		Departing Dec 11, 2026

    From

    $108

    Last seen: 5 hours ago

    *Prices found by others in the previous 48 hours for one-way flights. Prices shown may also require membership in our travel club, Discount Den®.

    Ontario/LA, CA Seattle, WA

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