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£53+ Cheap flights from Ontario

This is the cheapest return flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 11/10. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
ONT — LHR
17 Oct — 24 Oct1
1 adult
1 adult, Economy

What to know about flights from Ontario

Discover essential information about flights departing from Ontario, including flight schedules, destinations, airlines operating at the Ontario airport, and any specific guidelines or requirements for travellers. Please note that the information is based on the most recent updates available. Data last updated 17 September 2025.

Cheapest one-way flight

£16

Cheapest round-trip flight

£38

Cheapest airline

Alaska Airlines

Most popular destination

London Heathrow (LHR)

Good round-trip deal

£63 or less

Good one-way deal

£122 or less
The cheapest one-way flight from Ontario is currently to San Francisco.
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The cheapest round-trip flight from Ontario is currently to Las Vegas Harry Reid Intl.
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On average, Alaska Airlines currently has the cheapest one-way flight from Ontario (avg. price of £99).
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London Heathrow (LHR) is currently the most popular flight destination from Ontario (average return price of £356).
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Price to beat on a round-trip flight from Ontario.
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Price to beat on a one-way flight from Ontario.
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Find flights from Ontario

Cheapest flights from Ontario
Explore the most affordable flight options available from Ontario. Find the lowest fares based on data from user searches, with prices last updated on 17 September 2025.

Wed 15/1017:50ONT - SEA
Nonstop2h 59mDelta
Sat 18/1019:55SEA - ONT
Nonstop2h 46mDelta
Deal found 16/9£98
Fri 7/1117:50ONT - SEA
Nonstop2h 59mDelta
Sun 9/1114:19SEA - ONT
Nonstop2h 50mDelta
Deal found 16/9£98
Fri 17/1016:35ONT - SEA
1 stop5h 47mDelta
Sun 19/1008:15SEA - ONT
Nonstop2h 53mDelta
Deal found 16/9£105
Thu 2/1019:30ONT - SEA
1 stop20h 15mFrontier
Sun 5/1013:22SEA - ONT
1 stop24h 38mFrontier
Deal found 16/9£106
Fri 10/1010:30ONT - SEA
Nonstop2h 56mFrontier
Wed 15/1020:43SEA - ONT
1 stop12h 52mFrontier
Deal found 16/9£111
Sat 18/1013:15ONT - SEA
1 stop5h 09mDelta
Sat 25/1013:30SEA - ONT
1 stop7h 50mDelta
Deal found 16/9£112
Tue 6/106:45ONT - SEA
Nonstop3h 04mDelta
Mon 12/119:55SEA - ONT
Nonstop2h 43mDelta
Deal found 16/9£114
Sat 24/105:30ONT - SEA
2 stops7h 35mSouthwest
Mon 26/106:05SEA - ONT
1 stop8h 30mSouthwest
Deal found 16/9£116
Sun 19/1007:35ONT - SEA
Nonstop3h 00mDelta
Wed 22/1014:24SEA - ONT
Nonstop2h 46mDelta
Deal found 16/9£118
Wed 8/1016:25ONT - SEA
1 stop6h 35mSouthwest
Thu 9/1006:15SEA - ONT
1 stop5h 55mSouthwest
Deal found 17/9£121
Mon 29/916:45ONT - LHR
1 stop12h 05mAmerican Airlines
Wed 15/1012:00LHR - ONT
1 stop15h 03mAmerican Airlines
Deal found 15/9£436
Sun 16/1111:45ONT - LHR
1 stop13h 15mDelta
Thu 27/1106:30LHR - ONT
2 stops19h 48mDelta
Deal found 15/9£436

Find flights from Ontario within your budget

 
Find flights departing from Ontario that match your specified budget. Filter results by price range, allowing you to narrow down options and find flights that fit within your financial constraints. Please note that the search results are based on data from user searches, with fares last updated on 17 September 2025. In the last 7 days, Cheapflights users made a total of 858,174 searches

Fly to

Heathrow

Route

Depart

Return

Price

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Thu 16/10

11:48-14:45

Nonstop2h 57m

Seattle/Tacoma Intl

Fri 24/10

19:55-22:41

Nonstop2h 46m

£98

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Fri 17/10

16:35-23:59

1 stop7h 24m

Seattle/Tacoma Intl

Sun 19/10

08:15-11:08

Nonstop2h 53m

£105

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Thu 16/10

16:35-23:59

1 stop7h 24m

Seattle/Tacoma Intl

Wed 22/10

14:24-17:10

Nonstop2h 46m

£105

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Sun 19/10

07:35-10:35

Nonstop3h 00m

Seattle/Tacoma Intl

Sat 25/10

13:30-21:20

1 stop7h 50m

£105

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Thu 16/10

16:35-23:59

1 stop7h 24m

Seattle/Tacoma Intl

Tue 21/10

05:25-12:14

1 stop6h 49m

£112

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Tue 6/1

06:45-09:49

Nonstop3h 04m

Seattle/Tacoma Intl

Mon 12/1

19:55-22:38

Nonstop2h 43m

£114

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Sun 19/10

07:35-10:35

Nonstop3h 00m

Seattle/Tacoma Intl

Fri 24/10

19:55-22:41

Nonstop2h 46m

£118

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Wed 5/11

08:40-16:30

2 stops7h 50m

Seattle/Tacoma Intl

Thu 6/11

05:50-09:50

1 stop4h 00m

£125

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Sun 19/10

07:35-10:35

Nonstop3h 00m

Seattle/Tacoma Intl

Tue 21/10

07:10-12:14

1 stop5h 04m

£125

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Mon 15/12

16:49-00:20

1 stop7h 31m

Seattle/Tacoma Intl

Fri 2/1

08:16-11:03

Nonstop2h 47m

£128

Flights are sorted by cheapest return flights first.

Deals found on 16/9

Showing 1-10 of 60 results
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Best time to book a flight from Ontario

Have a flexible travel schedule? Discover the best time to fly from Ontario with our price prediction graph.
Estimated return price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Travel insights for flights from Ontario

Get recent, data-driven insights about flights from Ontario including ideal travel times, pricing trends, and more.

When is the best time to book a flight from Ontario?

Use this chart to determine the optimal time to book a return flight from Ontario to Heathrow. Price data was last updated on 12 September 2025.

Booking 62 days in advance of your planned departure date is, on average, the best time to get cheap flights from Ontario. The general trend is that the closer you book to the departure date, the more expensive your flight will be.

What is the cheapest month to book a flight from Ontario?

Currently, January is the cheapest month in which you can book a flight from Ontario (average of £322). Flying from Ontario in June will prove the most costly (average of £513). There are multiple factors that influence the price of a flight so comparing airlines, departure airports and times can help keep costs down.

What are popular destinations to fly to from Ontario?

If you’re flying from Ontario, these routes are more frequently taken by airlines Dallas (113 flights per day), Seattle (109 flights per day) and Atlanta (82 flights per day).

Portland
Portland
From £86
Taipei City Taiwan Taoyuan Intl
Taipei City Taiwan Taoyuan Intl
From £694
Phoenix Sky Harbor Intl
Phoenix Sky Harbor Intl
From £252
Charlotte Douglas
Charlotte Douglas
From £166

What is the cheapest place to fly to from Ontario?

The cheapest city to fly to from Ontario is Portland, with prices starting at £63. Explore other affordable destinations below.

Portland
Portland
From £86
Charlotte Douglas
Charlotte Douglas
From £166
Phoenix Sky Harbor Intl
Phoenix Sky Harbor Intl
From £252
Taipei City Taiwan Taoyuan Intl
Taipei City Taiwan Taoyuan Intl
From £694

Browse thousands of different options on Cheapflights for your next trip

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Related info for your journey

Access useful and relevant information related to your journey from Ontario. This can include details such as airport transportation, visa requirements, travel insurance, luggage regulations, and any other information that can ensure a smooth and hassle-free travel experience. Please note that the information is based on general guidance and may need to be verified with official sources. Data last updated 17 September 2025.

  • What are the most popular destinations to fly to from Ontario?

    This month, the top selected destinations from Ontario are Denver, Dallas/Fort Worth Airport, Honolulu. Throughout the year, Dallas/Fort Worth Airport, Denver, Guadalajara are some of the top choices made by users flying from Ontario.

  • What is the cheapest flight from Ontario to anywhere?

    Users have flown out of Ontario for as low as £63 to Portland (prices may vary depending on the airline and departure time). On average, users have booked flights for £312 to fly from Ontario.

  • What is the cheapest month to fly from Ontario?

    At the present moment the cheapest month to fly from Ontario is currently January; with June being the most expensive. Prices will vary depending on multiple factors such as booking in advance, airline and departure airports and times.

  • Where are the cheapest places to fly to from Ontario?

    Check out the cheapest flights from Ontario to embark to:
    Travel from Ontario to London from £436 round trip

  • How does Cheapflights help users find flights from Ontario?

    Deals for flights from Ontario are sourced from 900+ travel sites when you use Cheapflights. When all flight results come back, Cheapflights lets you sort and filter flights using different criteria to choose to your preference, such as price, airport, cabin class, and plenty of other options.

  • Why should you use Cheapflights to find cheap flight tickets from Ontario?

    It’s simple! Cheapflights, which is free to use for everyone, saves millions of users time and money every year by helping them find the cheapest and most suitable flights from Ontario.

  • Can Cheapflights find flights from Ontario with no change fees?

    Yes! Cheapflights helps users easily find flights from Ontario with no change fees.

  • Can Cheapflights notify me if prices for flights from Ontario become cheaper?

    Yes, Cheapflights has a feature called Price Alerts, which offers users the ability to be notified when flight prices change. Track prices for your flight from Ontario today and book when you’re ready!

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Fly with Cheapflights

Find the best flight deals on Cheapflights, where travellers can enjoy low prices and a wide availability of flights to their desired destinations.

How does Cheapflights help users find flights from Ontario?

Deals for flights from Ontario are sourced from 900+ travel sites when you use Cheapflights. When all flight results come back, Cheapflights lets you sort and filter flights using different criteria to choose to your preference, such as price, airport, cabin class, and plenty of other options.

Why should you use Cheapflights to find cheap flight tickets from Ontario?

It’s simple! Cheapflights, which is free to use for everyone, saves millions of users time and money every year by helping them find the cheapest and most suitable flights from Ontario.

Can Cheapflights find flights from Ontario with no change fees?

Yes! Cheapflights helps users easily find flights from Ontario with no change fees.

Can Cheapflights notify me if prices for flights from Ontario become cheaper?

Yes, Cheapflights has a feature called Price Alerts, which offers users the ability to be notified when flight prices change. Track prices for your flight from Ontario today and book when you’re ready!

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