Cheap Flight Tickets from Ontario (ONT) to Seattle (SEA), Starting at $103

Good to Know: Cheapest and Fastest ONT - SEA Flights

Useful information for finding best airline tickets from Ontario International to Seattle Tacoma International on your next trip.

Cheapest Round Trip Flight

$201

WN Southwest Airlines • 1 stop • 5h 50m

Sep 26 – Sep 27

The cheapest round trip flight from Ontario to Seattle (ONT-SEA-ONT) is currently $201

🔍 Search Flights

Cheapest One way Flight

$103

AS Alaska Airlines • 1 stop • 8h 32m

Sep 20

The cheapest one way flight from Ontario to Seattle (ONT-SEA) is currently $103

🔍 Search Flights

Cheapest Direct Flight

$287

DL Delta Airlines • nonstop • 4h 10m

Sep 25

The cheapest nonstop flight from Ontario to Seattle (ONT-SEA) is currently $287

🔍 Search Flights

Fastest Flight

4h 2m

The fastest nonstop flight from Ontario to Seattle (ONT-SEA) takes 4h 2m

Top Airlines Flying from Ontario to Seattle

Southwest Airlines-WN

Southwest Airlines

Delta Airline, DL

Delta Airlines

Alaska Airlines -AS

Alaska Airlines

Latest Flight Deals from Ontario (ONT) to Seattle (SEA)

Compare and book low fare round-trip air tickets from Ontario to Seattle. Ideal for travelers with confirmed return itineraries.

Sep 26 - Sep 27, Economy
WN
Ontario → Seattle
5h 50m
10:35 AM - 2:25 PM • 1 stop
WN
Ontario → Seattle
7h
7:05 AM - 11:25 AM • 1 stop
$201
Southwest Airlines
Sep 25 - Sep 26, Economy
DL
Ontario → Seattle
4h 10m
6:00 PM - 8:50 PM • nonstop
DL
Ontario → Seattle
4h 7m
5:55 PM - 8:42 PM • nonstop
$287
Delta Airlines
Sep 25 - Sep 26, Economy
DL
Ontario → Seattle
10h 44m
5:15 PM - 11:59 PM • 1 stop
DL
Ontario → Seattle
4h 7m
5:55 PM - 8:42 PM • nonstop
$290
Delta Airlines
Sep 25 - Sep 26, Economy
DL
Ontario → Seattle
5h
6:00 AM - 9:00 AM • nonstop
DL
Ontario → Seattle
10h 29m
5:45 AM - 12:14 PM • 1 stop
$297
Delta Airlines
Sep 25 - Sep 26, Economy
AS
Ontario → Seattle
4h 2m
3:14 PM - 5:56 PM • nonstop
AS
Ontario → Seattle
4h 9m
11:13 AM - 2:02 PM • nonstop
$402
Alaska Airlines
Sep 25 - Sep 26, Economy
AS
Ontario → Seattle
4h 3m
12:12 PM - 2:55 PM • nonstop
AS
Ontario → Seattle
9h 1m
12:21 PM - 6:02 PM • 1 stop
$405
Alaska Airlines

Fly from Ontario to Seattle with the Best Airfare Deals on FareLeaders

Looking for a cheap last-minute deal or the best round-trip flight from Ontario to Seattle? Find the biggest savings on one-way and round-trip tickets right here.

FAQs on Ontario to Seattle Flights

What are the airports in Ontario?
ONT
What’s the most popular airline flying from ONT to SEA?
The most popular airline flying from Ontario to Seattle are
Can I fly from ONT to SEA non-stop?
Yes, you can fly ONT to SEA non-stop on
Which airlines fly nonstop between Ontario and Seattle?
The non-stop flights between Ontario and Seattle are .
What’s the earliest departure time from ONT to SEA Airport?
The earliest flight leaves ONT at 6:00 am and lands in SEA - Seattle Tacoma International
What are the airports in Seattle?
SEA
Can I make changes to my Ontario to Seattle flight tickets or cancel them on FareLeaders.com?
No. We are an airfare comparison site. All the tickets are booked by the travel agent offering the flight deal and any changes or cancellations to be made are directly done directly by them or the airlines.
Can I cancel my flight tickets from ONT to SEA?
Read the fare rules of the Ontario to Seattle air tickets booked. Some airlines allow you to cancel the tickets within a stipulated time period with a cancellation fee.
Which airline alliances offer flights from Ontario and Seattle?
operate flights between Ontario and Seattle
How long does a flight from Ontario to Seattle take?
It takes approximately 3 hour to fly non-stop from ONT to SEA, which is 956.13 miles by air.
Which airlines provide the cheapest flights from Ontario (ONT) to Seattle (SEA) ?
In the past couple of days, the cheapest tickets to SEA from ONT were found on AS : USD 103
Do I need a passport to fly between ONT and SEA?
No
What’s the latest departure time from ONT to SEA ?
The last flight leaves ONT at 7:59 pm

Ontario (ONT) to Seattle (SEA): Airport Information

Origin Airport Ontario International , Ontario, US
Destination Airport Seattle Tacoma International , Seattle, US
Distance 956 miles

More Flight Options for Ontario (ONT) and Seattle (SEA)

Why Fareleaders for ONT to SEA Plane Tickets

Lowest Prices
Lowest Prices
Uncover the best deals on Ontario to Seattle flights by comparing fares from hundreds of airlines and agencies.
New Deals
New Deals Everyday
Get the best prices on ONT to SEA flights—we update our fares daily so you never miss a saving.
Best Travel Options
No Service Fees
Compare hundreds of Ontario to Seattle flights and secure the best deals—we never add any service fees.
Get Fare Drop Alert
Be the first to know when fares drop for the Ontario (ONT) to Seattle (SEA)
Terms and Conditions*