Southwest® flights from Ontario/LA to Seattle/Tacoma from $134

Promo Code

Low fares from Ontario/LA to Seattle/Tacoma

$

Ontario/LA (ONT)to

Seattle/Tacoma (SEA)
Depart: 12/02/2026

One-way

Basic

From
$134
Seen: 3 hrs ago

Ontario/LA (ONT)to

Seattle/Tacoma (SEA)
Depart: 11/05/2026

One-way

Basic

From
$139
Seen: 2 hrs ago

Ontario/LA (ONT)to

Seattle/Tacoma (SEA)
Depart: 11/09/2026

One-way

Basic

From
$139
Seen: 23 hrs ago

Ontario/LA (ONT)to

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

One-way

Basic

From
$144
Seen: 13 hrs ago

Ontario/LA (ONT)to

Seattle/Tacoma (SEA)
Depart: 11/04/2026

One-way

Basic

From
$144
Seen: 14 hrs ago

Ontario/LA (ONT)to

Seattle/Tacoma (SEA)
Depart: 11/10/2026

One-way

Basic

From
$144
Seen: 8 hrs ago

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Explore flights from Ontario/LA to Seattle/Tacoma

Oct 2026
From$154*
Seen: 5 hrs ago
One Way/Basic
Nov 2026
From$139*
Seen: 2 hrs ago
One Way/Basic
Dec 2026
From$134*
Seen: 3 hrs ago
One Way/Basic
cmp-daily-histogram-bars-legend-min-price-aria-label $154
cmp-daily-histogram-bars-legend-max-price-aria-label $333
Displaying fares for October-2026
  • ONT–SEA, 10/02/2026: From $333
    02

    Fri

    OCT

  • ONT–SEA, 10/03/2026: From $292
    03

    Sat

  • ONT–SEA, 10/04/2026: From $333
    04

    Sun

  • ONT–SEA, 10/05/2026: From $333
    05

    Mon

  • ONT–SEA, 10/06/2026: From $282
    06

    Tue

  • ONT–SEA, 10/07/2026: From $282
    07

    Wed

  • ONT–SEA, 10/08/2026: From $333
    08

    Thu

  • ONT–SEA, 10/09/2026: From $333
    09

    Fri

  • ONT–SEA: cmp-view-offers-disclaimer. Find Offers
    10

    Sat

  • ONT–SEA: cmp-view-offers-disclaimer. Find Offers
    11

    Sun

  • ONT–SEA, 10/12/2026: From $333
    12

    Mon

  • ONT–SEA, 10/13/2026: From $292
    13

    Tue

  • ONT–SEA: cmp-view-offers-disclaimer. Find Offers
    14

    Wed

  • ONT–SEA, 10/15/2026: From $264
    15

    Thu

  • ONT–SEA, 10/16/2026: From $264
    16

    Fri

  • ONT–SEA, 10/17/2026: From $254
    17

    Sat

  • ONT–SEA, 10/18/2026: From $264
    18

    Sun

  • ONT–SEA, 10/19/2026: From $264
    19

    Mon

  • ONT–SEA, 10/20/2026: From $264
    20

    Tue

  • ONT–SEA, 10/21/2026: From $189
    21

    Wed

  • ONT–SEA, 10/22/2026: From $189
    22

    Thu

  • ONT–SEA, 10/23/2026: From $205
    23

    Fri

  • ONT–SEA, 10/24/2026: From $189
    24

    Sat

  • ONT–SEA: cmp-view-offers-disclaimer. Find Offers
    25

    Sun

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

    Mon

  • ONT–SEA, 10/27/2026: From $189
    27

    Tue

  • ONT–SEA: cmp-view-offers-disclaimer. Find Offers
    28

    Wed

  • ONT–SEA, 10/29/2026: From $189
    29

    Thu

  • ONT–SEA, 10/30/2026: From $154
    30

    Fri

  • ONT–SEA: cmp-view-offers-disclaimer. Find Offers
    31

    Sat

  • ONT–SEA, 11/01/2026: From $209
    01

    Sun

    NOV

    • Range$154-$333

    *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

    Route Information

    148† Weekly flights

    † Weekly flights based on DOT published scheduled average flights Monday through Sunday between 9/1/2025 and 9/30/2025. Note: route may not operate every day of the week.

    ‡ Nonstop flights based on DOT published scheduled average flights Monday through Sunday between 9/1/2025 and 9/30/2025.

    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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