Flights from Ontario/LA, CA to Seattle, WA

Promo Code

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

Try alternate month or interact with individual days below in order to find offers.
Sep 2026
No results for this month.
Oct 2026
from$87*
Last seen: 22 hours ago
One-way/Economy
Nov 2026
from$74*
Last seen: 9 hours ago
One-way/Economy
cmp-daily-histogram-bars-legend-min-price-aria-label $99
cmp-daily-histogram-bars-legend-max-price-aria-label $247
Displaying fares for September-2026
  • ONT–SEA: cmp-view-offers-disclaimer. Find Offers
    29

    Tue

    SEP

  • ONT–SEA: cmp-view-offers-disclaimer. Find Offers
    30

    Wed

  • ONT–SEA: cmp-view-offers-disclaimer. Find Offers
    01

    Thu

    OCT

  • ONT–SEA, Oct 2, 2026: from $214
    02

    Fri

  • ONT–SEA, Oct 3, 2026: from $191
    03

    Sat

  • ONT–SEA, Oct 4, 2026: from $214
    04

    Sun

  • ONT–SEA, Oct 5, 2026: from $214
    05

    Mon

  • ONT–SEA: cmp-view-offers-disclaimer. Find Offers
    06

    Tue

  • ONT–SEA, Oct 7, 2026: from $206
    07

    Wed

  • ONT–SEA, Oct 8, 2026: from $214
    08

    Thu

  • ONT–SEA, Oct 9, 2026: from $247
    09

    Fri

  • ONT–SEA, Oct 10, 2026: from $191
    10

    Sat

  • ONT–SEA, Oct 11, 2026: from $214
    11

    Sun

  • ONT–SEA: cmp-view-offers-disclaimer. Find Offers
    12

    Mon

  • ONT–SEA, Oct 13, 2026: from $209
    13

    Tue

  • ONT–SEA, Oct 14, 2026: from $209
    14

    Wed

  • ONT–SEA, Oct 15, 2026: from $153
    15

    Thu

  • ONT–SEA, Oct 16, 2026: from $153
    16

    Fri

  • ONT–SEA, Oct 17, 2026: from $196
    17

    Sat

  • ONT–SEA, Oct 18, 2026: from $163
    18

    Sun

  • ONT–SEA, Oct 19, 2026: from $143
    19

    Mon

  • ONT–SEA, Oct 20, 2026: from $105
    20

    Tue

  • ONT–SEA, Oct 21, 2026: from $105
    21

    Wed

  • ONT–SEA, Oct 22, 2026: from $99
    22

    Thu

  • ONT–SEA, Oct 23, 2026: from $105
    23

    Fri

  • ONT–SEA: cmp-view-offers-disclaimer. Find Offers
    24

    Sat

  • ONT–SEA, Oct 25, 2026: from $105
    25

    Sun

  • ONT–SEA, Oct 26, 2026: from $105
    26

    Mon

  • ONT–SEA, Oct 27, 2026: from $111
    27

    Tue

  • ONT–SEA, Oct 28, 2026: from $105
    28

    Wed

    • Range$99-$247

    *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 Jan 20, 2027

    From

    $135

    Last seen: 4 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

    Barclays Badge

    Earn up to 60,000 Miles after qualifying activity. Terms apply.