Find Cheap Flights from Seattle/Tacoma Intl to Ontario (SEA - ONT)

Search hundreds of travel sites at once for deals on flights to Ontario

Mon 12/18
Mon 12/25
Any month
Compare vs. KAYAK |

Good to Know

Low Season:
January
Best time to beat the crowds
3%
expected price decrease
High Season:
June
Most popular time to fly
11%
expected price increase
Average Price:
$266
(avg. price over the last 2 weeks)
Good Deal:
$186
or less (round trip)

When to Book Flights from Seattle/Tacoma Intl to Ontario

Average price per month
Flight prices as travel date approaches
-1 day
-2 days

Top tips for Finding a Cheap Flight

Looking for a cheap flight? 25% of our users found flights on this route for $186 or less.
The cheapest flight from Seattle/Tacoma Intl to Ontario was found 90 days before departure, on average.
Book at least 6 weeks before departure in order to get a below-average price.
High season is considered to be May, June and July. The cheapest month to fly is January.
Morning departure is around 12% cheaper than an evening flight, on average*.
*Average of the lowest prices shown in KAYAK’s search results for departures within the next 30 days

FAQs for Booking Seattle/Tacoma Intl to Ontario Flights

How long does a flight from Seattle/Tacoma Intl to Ontario take?
An average nonstop flight takes 2h 30m, covering a distance of 957 miles.
How many flights are there between Seattle/Tacoma Intl and Ontario?
There are 152 (nonstop) flights between Seattle/Tacoma Intl and Ontario per week, averaging 20 per day.
Which airlines provide the cheapest flights from Seattle/Tacoma Intl to Ontario?
In the past 3 days, the cheapest round-trip tickets were found on United ($150), Multiple Airlines ($177) and Frontier ($208).
Do I need a passport to fly between Seattle/Tacoma Intl and Ontario?
No.
Which airlines fly most frequently between Seattle/Tacoma Intl and Ontario?
American Airlines (10 times daily), Alaska Airlines (10 times daily), Air France (1 times daily) are the most frequent flyers on this route.
What’s the cheapest day of the week to fly Seattle/Tacoma Intl to Ontario?
For Seattle/Tacoma Intl to Ontario, Friday is the cheapest day to fly on average and Sunday is the most expensive. Flying from Ontario back to Seattle/Tacoma Intl, the best deals are generally found on Wednesday, with Tuesday being the most expensive.

Book cheap flights from Seattle/Tacoma Intl to Ontario (round-trip)

Airports
Origin
Seattle
$150
only
$150
Destination
Ontario
$150
only
$150
Fri, Jan 5
SEA
ONT
4h 52m
Sat, Jan 6
ONT
SEA
6h 43m
Trip: 2 days
7.0GoodShow reviews
Overall 7.0 Good
Based on 52387 reviews
Overall
7.2
Boarding
7.4
Comfort
6.9
Crew
7.7
Entertainment
6.5
Food
6.4
ATL
IAH
Excellent 10.0

Everything was wonderful thank you so much

IAH
FLL
Excellent 10.0

No variety of snacks options

IAH
BJX
Excellent 10.0

Service is great fly on time

COS
DEN
Excellent 8.0

Nice staff, helpful front desk and flight attendants.

No wifi, carry on fee, small seats

IAH
CUN
Excellent 8.3

being my first time flying international everything went smooth. The staff was very helpful.

This flight went smooth, I was very pleased with it.

Sat, Mar 3
SEA
ONT
4h 55m
Tue, Mar 6
ONT
SEA
6h 52m
Trip: 4 days
Overall 0.0 Poor
Based on 0 reviews
Sun, Feb 11
SEA
ONT
18h 01m
Sat, Feb 17
ONT
SEA
6h 20m
Trip: 7 days
5.6OkayShow reviews
Overall 5.6 Okay
Based on 33276 reviews
Overall
5.9
Boarding
6.4
Comfort
5.4
Crew
6.8
Entertainment
4.5
Food
4.7
MSY
PVD
Excellent 8.0

The price!

DEN
MKE
Good 6.6

Direct flight from Denver to Milwaukee. Didn't have to wait on tarmac so that was a plus.

Have to pay for every little thring down to the peanuts

TYS
MCO
Okay 5.0

Great people

The plane wasn’t very clean

AUS
LAS
Excellent 8.0

Efficient

N/a

DEN
MCO
Excellent 8.0

The fact that my checked baggage is confusing when they charged me it was only for one way. I was billed and then noticed it was only one way, so I had to re enter my credit card info twice. Seems to me they should assume I will be bringing back my suitcase and contents rather than that I would be leaving it.

Sat, Apr 7
SEA
ONT
2h 30m
Wed, Apr 11
ONT
SEA
2h 40m
Trip: 5 days
7.2GoodShow reviews
Overall 7.2 Good
Based on 26083 reviews
Overall
7.3
Boarding
7.5
Comfort
7.1
Crew
7.8
Entertainment
6.7
Food
6.6
LHR
DFW
Good 6.3

The gate was not suitable for so many people . It was very cold in the airplane

SJU
PHL
Good 6.3

My screen was not responsive most of the time

HND
LAX
Okay 4.0

This flight was miserable. Seriously, one of the worst flight experiences I've ever had. The leg room was absurdly small. I'm not a tall person and I only had one inch in front of my legs. When the guy in front of me put his seat back it pressed into my knees. There wasn't enough space to bend down and untie my shoes, let alone get something out of my bag. My shoulder and knee were touching the guy next to me (a complete stranger) for the entire flight and there was nothing I could do about it. This was a red-eye but I absolutely could not sleep because it was so uncomfortable, so when we landed I had a terrible migraine and was nauseous and disoriented going through customs. I actually had to sit down in the airport because I though I was gonna pass out while trying to carry my bag, that's how shitty I felt after this flight. On top of that, not being able to sleep on the flight really messed up my sleep schedule and so jet lag from the time change has been made even worse, so I'm completely out of whack and its so much worse that it otherwise would have been because of the horrible flight. Also the food was gross and there wasn't enough of it. Even now, I don't think I have really communicated just how shitty this flight was. I was actually angry when I saw my seat upon boarding, and I'm still angry about it now.

DFW
SCQ
Okay 4.0

This is a modern airplane with great features

The seats are way to narrow

PHX
PDX
Excellent 9.0

I like how quick and efficient the boarding and check in process was.

I just wish that if I paid a little more for seats I should get more comfortable and roomier seats is all. Don’t make the seats sit so upright.

Thu, Feb 1
SEA
ONT
7h 14m
Tue, Feb 6
ONT
SEA
4h 55m
Trip: 6 days
7.0GoodShow reviews
Overall 7.0 Good
Based on 52387 reviews
Overall
7.2
Boarding
7.4
Comfort
6.9
Crew
7.7
Entertainment
6.5
Food
6.4
IAH
BJX
Excellent 10.0

Service is great fly on time

IAH
CUN
Excellent 8.3

being my first time flying international everything went smooth. The staff was very helpful.

This flight went smooth, I was very pleased with it.

ORD
LHR
Excellent 9.6

Very limited movie choices on this 767 aircraft

ATL
IAH
Excellent 10.0

Everything was wonderful thank you so much

ITO
LAX
Mediocre 2.0

See below

See below

Mon, Feb 26
SEA
ONT
4h 37m
Tue, Feb 27
ONT
SEA
6h 24m
Trip: 2 days
7.0GoodShow reviews
Overall 7.0 Good
Based on 52387 reviews
Overall
7.2
Boarding
7.4
Comfort
6.9
Crew
7.7
Entertainment
6.5
Food
6.4
ATL
IAH
Excellent 10.0

Everything was wonderful thank you so much

IAH
CUN
Excellent 8.3

being my first time flying international everything went smooth. The staff was very helpful.

This flight went smooth, I was very pleased with it.

IAH
BJX
Excellent 10.0

Service is great fly on time

PVR
ORD
Excellent 8.0

Arrived earlier than expected.

Waited an hour for the gate to be vacate by another plane.

ITO
LAX
Mediocre 2.0

See below

See below

Sat, Mar 3
SEA
ONT
4h 37m
Tue, Mar 6
ONT
SEA
6h 52m
Trip: 4 days
7.0GoodShow reviews
Overall 7.0 Good
Based on 52387 reviews
Overall
7.2
Boarding
7.4
Comfort
6.9
Crew
7.7
Entertainment
6.5
Food
6.4
IAH
BJX
Excellent 10.0

Service is great fly on time

COS
DEN
Excellent 8.0

Nice staff, helpful front desk and flight attendants.

No wifi, carry on fee, small seats

LAX
AUS
Mediocre 2.0

We did not crash. Eventually we got to our destination.

All flights were awful. None were on time. I paid for economy plus aisle seat but was put in economy middle seat anyway. Asked for refund and was sent to 3 different people. The final person, a gate agent for my departing gate, Peggy Hunter, told me that she has 35 years experience and she knows everything about United Airlines’ processes. Told me the only way I might get a refund is to submit online but that paying extra for a seat upgrade doesn’t mean I will actually get one and that I should read the fine print on the ticket. Had previously spoken to another gate agent who had told me that I could ask for a refund at the departing gate. Wifi didn’t work. On one of three delayed flights had to beg for water to take my medicine. I will make extra efforts to avoid using this mediocre airline.

ORD
LHR
Excellent 9.6

Very limited movie choices on this 767 aircraft

PVR
ORD
Excellent 8.0

Arrived earlier than expected.

Waited an hour for the gate to be vacate by another plane.

Thu, May 3
SEA
ONT
5h 52m
Sun, May 6
ONT
SEA
13h 50m
Trip: 4 days
Overall 0.0 Poor
Based on 0 reviews
Sat, Mar 3
SEA
ONT
4h 37m
Tue, Mar 6
ONT
SEA
6h 52m
Trip: 4 days
7.0GoodShow reviews
Overall 7.0 Good
Based on 52387 reviews
Overall
7.2
Boarding
7.4
Comfort
6.9
Crew
7.7
Entertainment
6.5
Food
6.4
IAH
FLL
Excellent 10.0

No variety of snacks options

COS
DEN
Excellent 8.0

Nice staff, helpful front desk and flight attendants.

No wifi, carry on fee, small seats

ORD
LHR
Excellent 9.6

Very limited movie choices on this 767 aircraft

LAX
AUS
Mediocre 2.0

We did not crash. Eventually we got to our destination.

All flights were awful. None were on time. I paid for economy plus aisle seat but was put in economy middle seat anyway. Asked for refund and was sent to 3 different people. The final person, a gate agent for my departing gate, Peggy Hunter, told me that she has 35 years experience and she knows everything about United Airlines’ processes. Told me the only way I might get a refund is to submit online but that paying extra for a seat upgrade doesn’t mean I will actually get one and that I should read the fine print on the ticket. Had previously spoken to another gate agent who had told me that I could ask for a refund at the departing gate. Wifi didn’t work. On one of three delayed flights had to beg for water to take my medicine. I will make extra efforts to avoid using this mediocre airline.

IAH
CUN
Excellent 8.3

being my first time flying international everything went smooth. The staff was very helpful.

This flight went smooth, I was very pleased with it.

Fri, Jun 15
SEA
ONT
4h 16m
Sat, Jun 16
ONT
SEA
6h 23m
Trip: 2 days
7.8GoodShow reviews
Overall 7.8 Good
Based on 14274 reviews
Overall
8.0
Boarding
8.1
Comfort
7.7
Crew
8.4
Entertainment
7.5
Food
7.3
JFK
PHX
Good 6.6

The crew was late so we were delayed two hours. I find that extremely infuriating when you are a passenger and have to show up two hours before your flight. I also would lose my job if I was two hours late for a client.

YYZ
ATL
Excellent 8.0

The boarding was very organised and the crew very friendly. The snacks that they offer is great too

FLL
DTW
Excellent 10.0

New plane with knight entertainment screens at all seats!

Delayed, bit crew was friendly and efficient!

SEA
SNA
Excellent 8.6

The wifi wasn't strong enough to download the app to watch movies on the plane.

AMS
DTW
Mediocre 2.0

The most horrible experience. Pathetic to say the least. No water in the flight lavotries. Such a pathetic service from so called top airline.

Fri, Jan 5
SEA
ONT
15h 55m
Sun, Jan 7
ONT
SEA
21h 21m
Trip: 3 days
5.6OkayShow reviews
Overall 5.6 Okay
Based on 33276 reviews
Overall
5.9
Boarding
6.4
Comfort
5.4
Crew
6.8
Entertainment
4.5
Food
4.7
TYS
MCO
Okay 5.0

Great people

The plane wasn’t very clean

DEN
SFO
Mediocre 2.0

Website would not let me check in the day before or the morning or my flight. There was an error every time and I almost got to the end once. I could not change the time of my transportation and arrived 10 minutes past the check in deadline (an hour prior to the flight taking off). I was refused access to the flight and offered a flight 5 hours later. The staff was rude and not helpful. I had heard negative things about Frontier and now I know why.

DEN
MCO
Excellent 8.0

The fact that my checked baggage is confusing when they charged me it was only for one way. I was billed and then noticed it was only one way, so I had to re enter my credit card info twice. Seems to me they should assume I will be bringing back my suitcase and contents rather than that I would be leaving it.

DEN
MKE
Good 6.6

Direct flight from Denver to Milwaukee. Didn't have to wait on tarmac so that was a plus.

Have to pay for every little thring down to the peanuts

MSY
MCO
Excellent 10.0

Great crew great flight

Nothing, everything was awesome. Crazy to believe this was a 19 dollar flight

Sat, Mar 3
SEA
ONT
4h 37m
Tue, Mar 6
ONT
SEA
6h 52m
Trip: 4 days
7.0GoodShow reviews
Overall 7.0 Good
Based on 52387 reviews
Overall
7.2
Boarding
7.4
Comfort
6.9
Crew
7.7
Entertainment
6.5
Food
6.4
IAH
FLL
Excellent 10.0

No variety of snacks options

COS
DEN
Excellent 8.0

Nice staff, helpful front desk and flight attendants.

No wifi, carry on fee, small seats

LAX
AUS
Mediocre 2.0

We did not crash. Eventually we got to our destination.

All flights were awful. None were on time. I paid for economy plus aisle seat but was put in economy middle seat anyway. Asked for refund and was sent to 3 different people. The final person, a gate agent for my departing gate, Peggy Hunter, told me that she has 35 years experience and she knows everything about United Airlines’ processes. Told me the only way I might get a refund is to submit online but that paying extra for a seat upgrade doesn’t mean I will actually get one and that I should read the fine print on the ticket. Had previously spoken to another gate agent who had told me that I could ask for a refund at the departing gate. Wifi didn’t work. On one of three delayed flights had to beg for water to take my medicine. I will make extra efforts to avoid using this mediocre airline.

PVR
ORD
Excellent 8.0

Arrived earlier than expected.

Waited an hour for the gate to be vacate by another plane.

IAH
CUN
Excellent 8.3

being my first time flying international everything went smooth. The staff was very helpful.

This flight went smooth, I was very pleased with it.

Sun, Dec 24
SEA
ONT
2h 33m
Mon, Dec 25
ONT
SEA
2h 36m
Trip: 2 days
8.4ExcellentShow reviews
Overall 8.4 Excellent
Based on 87 reviews
Overall
8.6
Boarding
8.7
Comfort
8.4
Crew
8.9
Entertainment
7.8
Food
8.0
SEA
ONT
Mediocre 2.0

The fact you cancelled and booked me the next day without making any effort for a flight you cancelled because of crew shortages. I am highly unlikely to risk flying with Horizon Airlines again.

SEA
ONT
Excellent 10.0

Had a very smooth experience the whole way through. friendly and considerate flight attendants and flight attendant students. Very fun and enthusiastic pilot crew. Got two drinks! They came they multiple times.

SEA
ONT
Okay 4.3

The flight was on time and the crew was efficient and courteous

Boarding was horrible (like most airlines), too many levels, and by the time we can board, we have a long wait in the loading corridor, at a standstill in the aisle. Seats are cramped and the only thing they offer to eat (free) is a small cookie. They charge too much for internet connection also. I wish airlines would just board from the last row forward, would speed the process up tremendously. I don't care about first class, MVP, military, families, they always seem to be in the front third, and that's what slows everything down.

SEA
ONT
Excellent 10.0

Loved the planes- clean and roomy in regular seats! The flight attendants were awesome. We are spoiled for any other airline now.... ;-)

SEA
ONT
Excellent 9.3

Flight on time and not over booked. Informative captain. Excellent prices.

Lacking elbow room.

Sun, Dec 31
SEA
ONT
2h 33m
Fri, Jan 5
ONT
SEA
4h 37m
Trip: 6 days
Overall 0.0 Poor
Based on 0 reviews
Sun, Feb 18
SEA
ONT
18h 01m
Fri, Feb 23
ONT
SEA
6h 20m
Trip: 6 days
5.6OkayShow reviews
Overall 5.6 Okay
Based on 33276 reviews
Overall
5.9
Boarding
6.4
Comfort
5.4
Crew
6.8
Entertainment
4.5
Food
4.7
SJU
ATL
Excellent 10.0

Fast luggage checking

No cash accepted for overweight baggage

PHL
MCO
Mediocre 2.3

Its a scam! They act like they are giving you a break by having you buy cheap flights but in reality it costs more than a bit more expensive flight. I had to pay $45.00 each bag no matter if it was checked or carry-on. In total round trip I paid $180.00 extra just for my husbands carry-on as well as mine. Must add that our flights together cost 286.00. We should of went with American Airlines. On top of that we couldn't select our own seat if so, we had to pay extra, so we had to sit separated from each other. It was ridiculous! Never Again with this company!!!!!

MSY
PVD
Excellent 8.0

The price!

LAS
IAD
Good 6.3

The staff on the flight was awesome, very helpful and kind to my friend who is terrified to fly. We were even ahead of schedule.

To pay for a carry on item is just crazy to me... not to mention you have to pay for beverages and snacks. All you are given is water.

DEN
SFO
Mediocre 2.0

Website would not let me check in the day before or the morning or my flight. There was an error every time and I almost got to the end once. I could not change the time of my transportation and arrived 10 minutes past the check in deadline (an hour prior to the flight taking off). I was refused access to the flight and offered a flight 5 hours later. The staff was rude and not helpful. I had heard negative things about Frontier and now I know why.

Mon, Jun 4
SEA
ONT
14h 43m
Fri, Jun 8
ONT
SEA
22h 06m
Trip: 5 days
5.6OkayShow reviews
Overall 5.6 Okay
Based on 33276 reviews
Overall
5.9
Boarding
6.4
Comfort
5.4
Crew
6.8
Entertainment
4.5
Food
4.7
SJU
ATL
Excellent 10.0

Fast luggage checking

No cash accepted for overweight baggage

TYS
MCO
Okay 5.0

Great people

The plane wasn’t very clean

LAS
IAD
Good 6.3

The staff on the flight was awesome, very helpful and kind to my friend who is terrified to fly. We were even ahead of schedule.

To pay for a carry on item is just crazy to me... not to mention you have to pay for beverages and snacks. All you are given is water.

LAX
DEN
Excellent 8.0

Good beer selection

Air conditioning Weak flow Warm temperatures Non reclining seats

DEN
MKE
Good 6.6

Direct flight from Denver to Milwaukee. Didn't have to wait on tarmac so that was a plus.

Have to pay for every little thring down to the peanuts

Sun, Apr 1
SEA
ONT
2h 34m
Thu, Apr 5
ONT
SEA
2h 40m
Trip: 5 days
7.2GoodShow reviews
Overall 7.2 Good
Based on 26083 reviews
Overall
7.3
Boarding
7.5
Comfort
7.1
Crew
7.8
Entertainment
6.7
Food
6.6
DFW
SCQ
Okay 4.0

This is a modern airplane with great features

The seats are way to narrow

JFK
MXP
Mediocre 2.0

6hours delay and no reimbursement. It sucked! Thank you.

DFW
LHR
Good 7.0

Crew were very nice.

Poor food for vegetarians. Also the overhead space was not locked properly. Suddenly, it opened and my carry on fell out. Luckily, it didn’t hit my husband who had the aisle seat or anyone else. However, I am upset because my laptop was inside this and may be damaged now.

DFW
IAH
Mediocre 3.3

The flight was delayed and my luggage is coming in the later flight. I need some form of consolation for this pathetic service.

PHL
CLT
Excellent 9.5

very nice seats.

Thu, May 24
SEA
ONT
4h 08m
Thu, May 31
ONT
SEA
5h 10m
Trip: 8 days
7.0GoodShow reviews
Overall 7.0 Good
Based on 52387 reviews
Overall
7.2
Boarding
7.4
Comfort
6.9
Crew
7.7
Entertainment
6.5
Food
6.4
IAH
BJX
Excellent 10.0

Service is great fly on time

ORD
LHR
Excellent 9.6

Very limited movie choices on this 767 aircraft

IAH
LFT
Okay 4.0

Never made it and had to go yet to another desk because it was a united flight this was the worst i have ever experienced

COS
IAH
Good 6.6

I really like how your flights are inexpensive compared to others when trying to purchase a last minute ticket.

The last two times I traveled ( I flew with United Airlines ) and both times my flights were delayed. The first time it was delayed by 4 hours and made me miss an appointment. The second time it was delayed by over 13 hours. It was nice that United had put me in a hotel room for the night, but again it took away from time in which I needed to be somewhere else.

IAH
CUN
Excellent 8.3

being my first time flying international everything went smooth. The staff was very helpful.

This flight went smooth, I was very pleased with it.

Sun, Dec 31
SEA
ONT
2h 33m
Thu, Jan 4
ONT
SEA
2h 36m
Trip: 5 days
Overall 0.0 Poor
Based on 0 reviews
Sun, Dec 31
SEA
ONT
5h 13m
Fri, Jan 5
ONT
SEA
4h 37m
Trip: 6 days
7.0GoodShow reviews
Overall 7.0 Good
Based on 52387 reviews
Overall
7.2
Boarding
7.4
Comfort
6.9
Crew
7.7
Entertainment
6.5
Food
6.4
LBB
IAH
Good 7.3

Paying for entertainment

ITO
LAX
Mediocre 2.0

See below

See below

PVR
ORD
Excellent 8.0

Arrived earlier than expected.

Waited an hour for the gate to be vacate by another plane.

ORD
LHR
Excellent 9.6

Very limited movie choices on this 767 aircraft

IAH
FLL
Excellent 10.0

No variety of snacks options

Show more results
*
Prices are per person and are for e–tickets and include all taxes & fees in USD.

We attempt to get accurate prices, however, prices are not guaranteed.

Here's why:

We’re not the seller.
At KAYAK we don’t set the prices, so it’s not possible for us to guarantee what other companies are selling.

We compile tonnes of data for you
Our service lets you quickly and easily compare results from hundreds of travel sites at once. In this sense, KAYAK is a search engine and we can't guarantee prices we find.

Why aren’t prices accurate 100% of the time?
Prices on airline seats, hotel rooms and car rentals can change frequently. Several people may also be trying to buy the same travel option simultaneously. As a result, you may find, on occasion, that certain prices are no longer available.

If you have more questions or if you have a bad price to report to us,
please send us an and someone from our team will get back to you promptly.

^
The fares displayed include all taxes and fees for economy class travel and were found by the provider in the last 72 hours. Seats are limited and may not be available on all flights and days. Fares are subject to change and may not be available on all flights or dates of travel. Some carriers charge additional fees for extra checked bags. Please check the carriers' sites.