HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
Ontario

$34+ Cheap flights from Ontario

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 7/23. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — SEA
Jul 23 — Jul 301
Wed 7/23
Wed 7/30
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

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 travelers. Please note that the information is based on the most recent updates available. Data last updated July 18, 2025.

Cheapest one-way flight

$33

Cheapest round-trip flight

$58

Cheapest airline

LEVEL

Most popular destination

Las Vegas Harry Reid Intl (LAS)

Good round-trip deal

$95 or less

Good one-way deal

$72 or less
The cheapest one-way flight from Ontario is currently to Las Vegas Harry Reid Intl.
Search Deals
The cheapest round-trip flight from Ontario is currently to Las Vegas Harry Reid Intl.
Search Deals
On average, LEVEL currently has the cheapest one-way flight from Ontario (avg. price of $671).
Search Deals
Las Vegas Harry Reid Intl (LAS) is currently the most popular flight destination from Ontario (average round-trip price of $89).
Search Deals
Price to beat on a round-trip flight from Ontario.
Search Deals
Price to beat on a one-way flight from Ontario.
Search Deals

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 July 18, 2025.

Thu 8/286:00 amONT - LAS
Nonstop1h 13mFrontier
Sun 8/316:30 amLAS - ONT
Nonstop1h 03mFrontier
Deal found 7/17$76
Wed 8/209:00 pmONT - LAS
Nonstop1h 10mSouthwest
Sat 8/238:50 amLAS - ONT
Nonstop1h 05mSouthwest
Deal found 7/17$77
Tue 8/56:39 pmONT - SFO
Nonstop1h 27mUnited Airlines
Tue 8/59:25 pmSFO - ONT
Nonstop1h 27mUnited Airlines
Deal found 7/15$79
Sun 8/319:41 pmONT - SFO
Nonstop1h 33mFrontier
Fri 9/510:11 pmSFO - ONT
Nonstop1h 27mFrontier
Deal found 7/15$87
Fri 10/1712:59 amONT - DEN
Nonstop2h 21mFrontier
Wed 10/2210:29 pmDEN - ONT
Nonstop2h 21mFrontier
Deal found 7/16$107
Sat 8/93:43 pmONT - PDX
Nonstop2h 23mFrontier
Sat 8/1612:25 pmPDX - ONT
Nonstop2h 23mFrontier
Deal found 7/16$114
Sat 8/234:56 pmONT - SEA
Nonstop2h 46mFrontier
Sun 8/311:20 pmSEA - ONT
Nonstop2h 54mFrontier
Deal found 7/15$150
Sat 10/185:25 amONT - DEN
Nonstop2h 10mSouthwest
Mon 10/2010:25 pmDEN - ONT
Nonstop2h 15mSouthwest
Deal found 7/15$157
Sat 9/201:42 pmONT - PDX
1 stop6h 55mUnited Airlines
Tue 9/301:44 pmPDX - ONT
1 stop3h 56mUnited Airlines
Deal found 7/16$159
Sat 9/276:00 amONT - SEA
Nonstop2h 54mDelta
Wed 10/17:50 pmSEA - ONT
Nonstop2h 50mDelta
Deal found 7/16$167
Tue 8/127:30 amONT - SEA
1 stop6h 55mAlaska Airlines
Tue 8/195:25 amSEA - ONT
1 stop3h 58mAlaska Airlines
Deal found 7/16$176
Sat 10/1111:15 amONT - PDX
Nonstop2h 19mHawaiian Airlines
Tue 10/147:40 amPDX - ONT
Nonstop2h 21mHawaiian Airlines
Deal found 7/17$177

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 July 18, 2025. In the last 7 days, Cheapflights users made a total of 2,558,603 searches

Fly to

Seattle

Route

Depart

Return

Price

OntarioLas Vegas

ONT - LAS

ONTLAS

Ontario

Thu 8/28

6:00 am-7:13 am

Nonstop1h 13m

Las Vegas Harry Reid Intl

Sun 8/31

6:30 am-7:33 am

Nonstop1h 03m

$76

OntarioLas Vegas

ONT - LAS

ONTLAS

Ontario

Wed 8/20

9:00 pm-10:10 pm

Nonstop1h 10m

Las Vegas Harry Reid Intl

Sat 8/23

8:50 am-9:55 am

Nonstop1h 05m

$77

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Tue 8/5

6:39 pm-8:06 pm

Nonstop1h 27m

San Francisco

Tue 8/5

9:25 pm-10:52 pm

Nonstop1h 27m

$79

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Fri 11/7

9:41 pm-11:13 pm

Nonstop1h 32m

San Francisco

Sun 11/9

10:11 pm-11:40 pm

Nonstop1h 29m

$86

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Fri 10/17

12:59 am-4:20 am

Nonstop2h 21m

Denver Intl

Wed 10/22

10:29 pm-11:50 pm

Nonstop2h 21m

$107

OntarioPortland

ONT - PDX

ONTPDX

Ontario

Sat 8/9

3:43 pm-6:06 pm

Nonstop2h 23m

Portland

Sat 8/16

12:25 pm-2:48 pm

Nonstop2h 23m

$114

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Mon 9/22

11:14 am-2:06 pm

Nonstop2h 52m

Seattle/Tacoma Intl

Thu 9/25

3:21 pm-6:01 pm

Nonstop2h 40m

$149

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Wed 9/3

6:05 pm-8:50 pm

Nonstop2h 45m

Seattle/Tacoma Intl

Tue 9/9

7:50 pm-10:42 pm

Nonstop2h 52m

$157

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Sat 10/18

5:25 am-8:35 am

Nonstop2h 10m

Denver Intl

Mon 10/20

10:25 pm-11:40 pm

Nonstop2h 15m

$157

OntarioPortland

ONT - PDX

ONTPDX

Ontario

Sat 9/20

1:42 pm-8:37 pm

1 stop6h 55m

Portland

Tue 9/30

1:44 pm-5:40 pm

1 stop3h 56m

$159

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/17

Showing 1-10 of 60 results
1
2
3
...
6

Ontario travel tips

Get helpful tips and advice for traveling to or from Ontario. Find recommendations for transportation, accommodations, local attractions, dining options, and other practical tips to enhance your travel experience. Please note that the travel tips are based on general knowledge and recommendations. Data last updated July 18, 2025.
  • If you are a member of the military, you can always go to the USO Lounge at Ontario International Airport (ONT), which provides free drinks, snacks, and access to high-speed Wi-Fi. It can be found directly across from Parking Lot F.
  • Parents will want to take note of the nursing rooms that are scattered throughout Ontario International Airport (ONT). These rooms provide parents with a comfortable place to tend to their children and contain amenities like padded benches, changing tables, and outlets.
  • Ontario International Airport (ONT) has several dining options to choose from, including a few fast-food restaurants, and sit-down restaurants that serve cuisines like American and Italian.

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 round-trip 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 round-trip flight from Ontario to Seattle. Price data was last updated on July 11, 2025.

To ensure you get the cheapest price possible for a flight from Ontario, you should look to book at least 90 days in advance of your intended travel date. The price of your flight may increase if you delay and leave booking until a week or so before departure.

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 $38). Flying from Ontario in July will prove the most costly (average of $118). There are multiple factors that influence the price of a flight so comparing airlines, departure airports and times can help keep costs down.

When is the cheapest time to fly from Ontario?

Use this chart to determine the cheapest time to fly round-trip from Ontario to Seattle. Price data was last updated on July 13, 2025.

Those who are seeking the cheapest fare on flights departing from Ontario would be wise to consider leaving during Thursday mornings when prices are typically at their lowest. When considering other options, price-conscious travelers should avoid Sunday evenings when fares are usually the most expensive.

Which airlines fly from Ontario?

For flights departing from Ontario check dates and pricing for the following: Frontier, Alaska Airlines, Delta, Hawaiian Airlines, Southwest. These airlines depart to the following popular destinations: Seattle.

Frontier
Frontier
From $20
American Airlines
American Airlines
From $130
Southwest
Southwest
From $97
China Airlines
China Airlines
From $602

What are popular destinations to fly to from Ontario?

Some of the most frequent flights departing from Ontario everyday are: Seattle (150 flights per day), Dallas (128 flights per day), and Atlanta (81 flights per day).

Las Vegas Harry Reid Intl
Las Vegas Harry Reid Intl
From $49
Denver Intl
Denver Intl
From $78
Seattle/Tacoma Intl
Seattle/Tacoma Intl
From $85
Dallas/Fort Worth
Dallas/Fort Worth
From $89

What is the cheapest place to fly to from Ontario?

The cheapest city to fly to from Ontario is San Francisco, with prices starting at $42. Explore other affordable destinations below.

San Francisco
San Francisco
From $42
Oakland
Oakland
From $48
Las Vegas Harry Reid Intl
Las Vegas Harry Reid Intl
From $49
Portland
Portland
From $58

Airline reviews for flights from Ontario

Read reviews and ratings of airlines operating flights from Ontario. Gain insights into the quality of service, in-flight amenities, customer experiences, and overall satisfaction to choose the best airline for your Ontario travel. Please note that the reviews are sourced from user searches and were last updated on July 18, 2025. In the last 7 days, Cheapflights users made a total of 2,558,603 searches.
Peruse reviews from past customers who have flown Alaska Airlines, Southwest, and Delta from Ontario to help guide your decision. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Entertainment

7.1

Food

7.1

Boarding

8.1

Comfort

7.8

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Entertainment

7.1

Food

7.1

Boarding

8.1

Comfort

7.8

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
Southwest
8.0
Very good
4,238 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Entertainment

7.1

Food

7.1

Boarding

8.1

Comfort

7.8

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
Delta
8.0
Very good
7,958 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Entertainment

7.1

Food

7.1

Boarding

8.1

Comfort

7.8

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
Hawaiian Airlines
7.8
Good
2,581 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Entertainment

7.1

Food

7.1

Boarding

8.1

Comfort

7.8

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
United Airlines
7.4
Good
8,864 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Entertainment

7.1

Food

7.1

Boarding

8.1

Comfort

7.8

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Popular international destinations from Ontario

The most popular international flight routes departing from Ontario we’ve come across at this time.
Flights from Ontario to Guadalajara
Flights from Ontario to San Salvador
Flights from Ontario to San José del Cabo
Flights from Ontario to León

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 July 18, 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 $42 to San Francisco (prices may vary depending on the airline and departure time). On average, users have booked flights for $529 to fly from Ontario.

  • What are the cheapest airlines flying from Ontario to anywhere?

    Over the past few days, we've found that Frontier, Spirit Airlines, and United Airlines have the cheapest prices from Ontario. Frontier flights from Ontario to Denver Arapahoe Co ($20), Spirit Airlines flights from Ontario to Atlanta Hartsfield-Jackson ($22), and United Airlines flights from Ontario to Abuja ($58).

  • What is the cheapest premium economy flight from Ontario?

    Options for some of the cheapest premium economy flights from Ontario we have found on Cheapflights are as follows:
    Fly from Ontario to Las Vegas starting at $73
    Fly from Ontario to Guadalajara starting at $433
    Fly from Ontario to Portland starting at $672
    Fly from Ontario to Salt Lake City starting at $877

  • What is the cheapest first class flight from Ontario?

    If you’re looking for a cheap first-class flight from Ontario, consider Las Vegas. Prices start at $78 so you can fly first-class even on a budget.

  • What is the cheapest month to fly from Ontario?

    January is currently the cheapest month to fly from Ontario. At this moment in time July is the most expensive month. These prices are determined by multiple factors and booking in advance can help keep costs down if your schedule is not as flexible.

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

    Check out the cheapest flights from Ontario to embark to:
    Fly from Ontario to San Francisco from $57 round trip
    Fly from Ontario to Las Vegas from $58 round trip
    Fly from Ontario to Phoenix from $97 round trip
    Fly from Ontario to San Jose from $97 round trip
    Fly from Ontario to Oakland from $97 round trip

  • What parking options are available at Ontario International Airport (ONT)?

    There are a few parking options available at Ontario International Airport (ONT), including over five different lots that provide short and long-term parking. You can also opt for premium parking, which will put you closer to your terminal.

  • How can I go from downtown Ontario to Ontario International Airport (ONT)?

    If you drive from downtown Ontario to Ontario International Airport (ONT), it will take around 5 to 10 minutes. With public transportation, like bus line 61, it will take you around 30 to 35 minutes instead.

  • Is there a hotel located directly at Ontario International Airport (ONT)?

    Ontario International Airport (ONT) does not have its own on-site hotel, but there are quite a few that are just a short distance from the transportation hub. The DoubleTree by Hilton Hotel Ontario Airport has a free shuttle and is less than a 15-minute drive away.

  • Does Ontario International Airport (ONT) have any pet relief areas?

    Ontario International Airport (ONT) has pet relief areas that are both indoors and outdoors. Indoor areas can be found in Terminals 2 and 4, while outdoor areas are located at the far end of each terminal building.

See more FAQs

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.