Southwest® flights from Ontario/LA to Seattle/Tacoma from $125

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Low fares from Ontario/LA to Seattle/Tacoma

$

Ontario/LA (ONT)to

Seattle/Tacoma (SEA)
Depart: 12/15/2026

One-way

Basic

From
$125
Seen: 17 hrs ago

Ontario/LA (ONT)to

Seattle/Tacoma (SEA)
Depart: 01/05/2027

One-way

Basic

From
$125
Seen: 11 hrs ago

Ontario/LA (ONT)to

Seattle/Tacoma (SEA)
Depart: 02/03/2027

One-way

Basic

From
$125
Seen: 4 minutes ago

Ontario/LA (ONT)to

Seattle/Tacoma (SEA)
Depart: 02/06/2027

One-way

Basic

From
$125
Seen: 12 hrs ago

Ontario/LA (ONT)to

Seattle/Tacoma (SEA)
Depart: 12/09/2026

One-way

Basic

From
$125
Seen: 21 hrs ago

Ontario/LA (ONT)to

Seattle/Tacoma (SEA)
Depart: 12/08/2026

One-way

Basic

From
$125
Seen: 9 hrs ago

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Explore flights from Ontario/LA to Seattle/Tacoma

Nov 2026
From$264*
Seen: 14 hrs ago
One Way/Basic
Dec 2026
From$125*
Seen: 17 hrs ago
One Way/Basic
Jan 2027
From$125*
Seen: 11 hrs ago
One Way/Basic
cmp-daily-histogram-bars-legend-min-price-aria-label $125
cmp-daily-histogram-bars-legend-max-price-aria-label $458
Displaying fares for November-2026
  • ONT–SEA: cmp-view-offers-disclaimer. Find Offers
    11

    Wed

    NOV

  • ONT–SEA, 11/12/2026: From $313
    12

    Thu

  • ONT–SEA: cmp-view-offers-disclaimer. Find Offers
    13

    Fri

  • ONT–SEA, 11/14/2026: From $284
    14

    Sat

  • ONT–SEA: cmp-view-offers-disclaimer. Find Offers
    15

    Sun

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

    Mon

  • ONT–SEA, 11/17/2026: From $284
    17

    Tue

  • ONT–SEA: cmp-view-offers-disclaimer. Find Offers
    18

    Wed

  • ONT–SEA: cmp-view-offers-disclaimer. Find Offers
    19

    Thu

  • ONT–SEA, 11/20/2026: From $313
    20

    Fri

  • ONT–SEA, 11/21/2026: From $284
    21

    Sat

  • ONT–SEA, 11/22/2026: From $313
    22

    Sun

  • ONT–SEA: cmp-view-offers-disclaimer. Find Offers
    23

    Mon

  • ONT–SEA, 11/24/2026: From $264
    24

    Tue

  • ONT–SEA, 11/25/2026: From $269
    25

    Wed

  • ONT–SEA: cmp-view-offers-disclaimer. Find Offers
    26

    Thu

  • ONT–SEA, 11/27/2026: From $274
    27

    Fri

  • ONT–SEA, 11/28/2026: From $324
    28

    Sat

  • ONT–SEA, 11/29/2026: From $458
    29

    Sun

  • ONT–SEA, 11/30/2026: From $264
    30

    Mon

  • ONT–SEA, 12/01/2026: From $269
    01

    Tue

    DEC

  • ONT–SEA, 12/02/2026: From $175
    02

    Wed

  • ONT–SEA, 12/03/2026: From $157
    03

    Thu

  • ONT–SEA, 12/04/2026: From $187
    04

    Fri

  • ONT–SEA, 12/05/2026: From $175
    05

    Sat

  • ONT–SEA, 12/06/2026: From $187
    06

    Sun

  • ONT–SEA, 12/07/2026: From $157
    07

    Mon

  • ONT–SEA, 12/08/2026: From $125
    08

    Tue

  • ONT–SEA, 12/09/2026: From $125
    09

    Wed

  • ONT–SEA, 12/10/2026: From $184
    10

    Thu

    • Range$125-$458

    *Fares displayed have been collected within the last 24 hours and may no longer be available at time of booking. Additional fees and charges for optional products and services may apply. Modifying this information may result in a different fare. To find the most updated fare, please visit Southwest.com. Fares listed are Basic, which are subject to additional terms and conditions.

    Flight Details

    Departing from:
    LA/Ontario International Airport
    Arriving at:
    Seattle/Tacoma International Airport
    Distance:
    956 miles

    Questions we hear the most

    There are 148 weekly flights from Ontario/LA to Seattle/Tacoma on Southwest Airlines.
    To find the lowest fares by day and time to fly Ontario/LA to Seattle/Tacoma with Southwest, check out our Low Fare Calendar.
    You can rent a car at Seattle/Tacoma International Airport book yours with your flight.
    Yes! Flights from Ontario/LA to Seattle/Tacoma—or from here or there to anywhere—can be changed with no change fees. Fare difference may apply.
    Check the status of your upcoming Southwest flight.
    Check out the Southwest Airlines® Help Center for answers about everything Southwest.

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