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Ontario

$29+ 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 5/19. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — SFO
May 3 — May 101
Sun 5/3
Sun 5/10
1 adult, Economy
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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 April 3, 2026. In the last 7 days, Cheapflights users made a total of 2,558,603 searches

Fly to

Route

Depart

Return

Price

Cheapest round-trip

OntarioLas Vegas

ONT - LAS

ONTLAS

Ontario

Wed 5/20

10:40 am-4:05 pm

1 stop5h 25m

Las Vegas Harry Reid Intl

Sat 5/23

5:40 am-11:05 am

1 stop5h 25m

$167

OntarioLas Vegas

ONT - LAS

ONTLAS

Ontario

Thu 6/4

5:15 pm-10:10 pm

1 stop4h 55m

Las Vegas Harry Reid Intl

Mon 6/8

6:20 am-11:20 am

1 stop5h 00m

$197

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Sat 5/2

6:20 pm-10:30 pm

1 stop4h 10m

Seattle/Tacoma Intl

Sat 5/9

5:45 am-2:10 pm

2 stops8h 25m

$202

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Mon 6/1

5:05 pm-12:10 am

2 stops7h 05m

San Francisco

Sat 6/6

5:00 am-8:40 am

1 stop3h 40m

$202

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Thu 5/7

10:39 am-1:30 pm

Nonstop2h 51m

Seattle/Tacoma Intl

Sat 5/9

7:50 pm-10:32 pm

Nonstop2h 42m

$207

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Fri 5/8

5:50 pm-8:50 pm

Nonstop3h 00m

Seattle/Tacoma Intl

Sun 5/10

8:25 am-11:12 am

Nonstop2h 47m

$217

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Wed 4/22

1:27 pm-2:56 pm

Nonstop1h 29m

San Francisco

Sat 5/2

8:10 am-9:41 am

Nonstop1h 31m

$217

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Tue 4/21

5:05 pm-10:29 pm

1 stop4h 24m

Denver Intl

Sat 4/25

12:30 pm-4:25 pm

1 stop4h 55m

$219

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Sat 5/2

5:30 am-12:20 pm

2 stops5h 50m

Denver Intl

Sat 5/9

12:50 pm-3:35 pm

1 stop3h 45m

$220

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Mon 5/4

1:55 pm-7:15 pm

1 stop4h 20m

Denver Intl

Tue 5/12

6:45 am-11:35 am

2 stops5h 50m

$224

Flights are sorted by cheapest round-trip flights first.

Deals found on 4/2

Showing 1-10 of 60 resultsSorted by cheapest first
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Compare providers for flights from Ontario

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Ontario in April
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*3 stars
CheapOairPrice Accuracy3 starsTrust Score*3 stars
eDreamsPrice Accuracy3 starsTrust Score*3 stars
CheapfaremartPrice Accuracy-Trust Score*1 star
Kiwi.comPrice Accuracy3 starsTrust Score*3 stars
JustAirTicketPrice Accuracy-Trust Score*1 star
Super.comPrice Accuracy-Trust Score*3 stars
CheapTicketsDealPrice Accuracy3 starsTrust Score*3 stars
CheapflightsfaresPrice Accuracy2 starsTrust Score*2 stars

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

  • Most accurate provider: Among all the travel providers offering deals on flights from Ontario, FlightHub has been found to have the most accurate pricing. Users can find the same prices on deals on Cheapflights as FlightHub about >95% of the time. This is based on searches for flights from Ontario made on Cheapflights over the past month and is updated monthly.
  • Most trusted provider: In terms of trustworthiness, Cheapflights users rate FlightHub the highest out of those offering flight deals from Ontario. FlightHub has a user feedback rating of 3 out of 3 stars (3 being the best) and has received the most positive sentiment from Cheapflights users searching for flights from Ontario. This info is gathered from Cheapflights searches over the past month.

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 April 3, 2026.
  • 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 San Francisco. Price data was last updated on April 2, 2026.

To ensure you get the cheapest price possible for a flight from Ontario, you should look to book at least 74 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, May is the cheapest month in which you can book a flight from Ontario (average of $28). Flying from Ontario in November will prove the most costly (average of $62). 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 San Francisco. Price data was last updated on March 28, 2026.

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

Which airlines fly from Ontario?

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

Frontier
Frontier
From $29
American Airlines
American Airlines
From $124
Southwest
Southwest
From $97
United Airlines
United Airlines
From $65

What are popular destinations to fly to from Ontario?

Some of the most frequent flights departing from Ontario everyday are: Seattle (92 flights per day), Dallas (85 flights per day), and Atlanta (67 flights per day).

Taipei City Taiwan Taoyuan Intl
Taipei City Taiwan Taoyuan Intl
From $389
Denver Intl
Denver Intl
From $96
Dallas/Fort Worth
Dallas/Fort Worth
From $113
Las Vegas Harry Reid Intl
Las Vegas Harry Reid Intl
From $53

What is the cheapest place to fly to from Ontario?

The cheapest city to fly to from Ontario is San José del Cabo Los Cabos, with prices starting at $40. Explore other affordable destinations below.

San José del Cabo Los Cabos
San José del Cabo Los Cabos
From $40
Morelia
Morelia
From $40
San Jose
San Jose
From $48
Las Vegas Harry Reid Intl
Las Vegas Harry Reid Intl
From $53

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 April 3, 2026. In the last 7 days, Cheapflights users made a total of 2,558,603 searches.
Peruse reviews from past customers who have flown Southwest,Alaska Airlines, andUnited Airlines from Ontario to help guide your decision. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.0
Very good
4,341 reviews

Overall

8.0

Crew

8.6

Comfort

8.0

Boarding

8.1

Food

7.0

Entertainment

7.5

Reviews

1 / 20
2.0
Mediocre

Dominic,Mar 2026

MCO - SMF

I had to try and sleep on the floor of the Austin airport. I spent 12 hours there. The airline policies were so poor, that a near violent argument broke out between the people in front of me and the flight attendants - making for a super stressful situation at 30,000 feet. Garbage airline choice by Kayak Garbage idea to book a flight with a layover. Next time I will pay for a quality booking myself, and somehow force the company to reimburse it.
Southwest
8.0
Very good
4,341 reviews
Southwest
8.0
Very good
4,341 reviews

Overall

8.0

Crew

8.6

Comfort

8.0

Boarding

8.1

Food

7.0

Entertainment

7.5

Reviews

1 / 20
2.0
Mediocre

Dominic,Mar 2026

MCO - SMF

I had to try and sleep on the floor of the Austin airport. I spent 12 hours there. The airline policies were so poor, that a near violent argument broke out between the people in front of me and the flight attendants - making for a super stressful situation at 30,000 feet. Garbage airline choice by Kayak Garbage idea to book a flight with a layover. Next time I will pay for a quality booking myself, and somehow force the company to reimburse it.
Alaska Airlines
7.9
Good
12,156 reviews
Southwest
8.0
Very good
4,341 reviews

Overall

8.0

Crew

8.6

Comfort

8.0

Boarding

8.1

Food

7.0

Entertainment

7.5

Reviews

1 / 20
2.0
Mediocre

Dominic,Mar 2026

MCO - SMF

I had to try and sleep on the floor of the Austin airport. I spent 12 hours there. The airline policies were so poor, that a near violent argument broke out between the people in front of me and the flight attendants - making for a super stressful situation at 30,000 feet. Garbage airline choice by Kayak Garbage idea to book a flight with a layover. Next time I will pay for a quality booking myself, and somehow force the company to reimburse it.
United Airlines
7.4
Good
9,538 reviews
Southwest
8.0
Very good
4,341 reviews

Overall

8.0

Crew

8.6

Comfort

8.0

Boarding

8.1

Food

7.0

Entertainment

7.5

Reviews

1 / 20
2.0
Mediocre

Dominic,Mar 2026

MCO - SMF

I had to try and sleep on the floor of the Austin airport. I spent 12 hours there. The airline policies were so poor, that a near violent argument broke out between the people in front of me and the flight attendants - making for a super stressful situation at 30,000 feet. Garbage airline choice by Kayak Garbage idea to book a flight with a layover. Next time I will pay for a quality booking myself, and somehow force the company to reimburse it.
Frontier
5.7
Fair
3,002 reviews
Southwest
8.0
Very good
4,341 reviews

Overall

8.0

Crew

8.6

Comfort

8.0

Boarding

8.1

Food

7.0

Entertainment

7.5

Reviews

1 / 20
2.0
Mediocre

Dominic,Mar 2026

MCO - SMF

I had to try and sleep on the floor of the Austin airport. I spent 12 hours there. The airline policies were so poor, that a near violent argument broke out between the people in front of me and the flight attendants - making for a super stressful situation at 30,000 feet. Garbage airline choice by Kayak Garbage idea to book a flight with a layover. Next time I will pay for a quality booking myself, and somehow force the company to reimburse it.

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 Morelia
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 April 3, 2026.

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

    This month, the top selected destinations from Ontario are Las Vegas, Dallas/Fort Worth Airport, Denver. Throughout the year, Las Vegas, Dallas/Fort Worth Airport, Denver 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 $40 to San José del Cabo (prices may vary depending on the airline and departure time). On average, users have booked flights for $493 to fly from Ontario.

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

    Over the past few days, we've found that Spirit Airlines, Frontier, and United Airlines have the cheapest prices from Ontario. Spirit Airlines flights from Ontario to Atlanta Hartsfield-Jackson ($27), Frontier flights from Ontario to Atlanta Hartsfield-Jackson ($29), and United Airlines flights from Ontario to Abuja ($65).

  • 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 $308
    Fly from Ontario to Guadalajara starting at $433
    Fly from Ontario to San Francisco starting at $461
    Fly from Ontario to Seattle starting at $557

  • 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 $122 so you can fly first-class even on a budget.

  • What is the cheapest month to fly from Ontario?

    May is currently the cheapest month to fly from Ontario. At this moment in time November 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 Las Vegas from $61 round trip
    Fly from Ontario to San Francisco from $66 round trip
    Fly from Ontario to Denver from $83 round trip
    Fly from Ontario to Seattle from $108 round trip
    Fly from Ontario to Houston from $109 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

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