HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
Fremont

$68+ Cheap flights from Ontario (ONT) to Fremont, CA

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 4/30. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — SFO
Apr 24 — May 11
Fri 4/24
Fri 5/1
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

Find cheap flights from Ontario to Fremont with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.
Cheapflights Tip: The best prices from Ontario to Fremont are usually found in May or April, booked 74 days in advance, depart on a Friday or Thursday and return on a Monday

Cheap flight deals from Ontario to Fremont

Cheapest flights from Ontario to Fremont
Explore the most affordable flight options available from Ontario to Fremont. Find the lowest fares from popular airlines and budget airlines, with prices last updated on March 25, 2026.

This Frontier deal was found by Cheapflights users on 3/25. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 5/58:17 pm
ONT
-
SFO
Nonstop1h 38m
Frontier
Wed 5/611:26 am
SFO
-
ONT
Nonstop1h 39m
Frontier
Deal found 3/25$116
This United Airlines deal was found by Cheapflights users on 3/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/1511:05 am
ONT
-
SFO
Nonstop1h 29m
United Airlines
Wed 4/2210:50 am
SFO
-
ONT
Nonstop1h 30m
United Airlines
Deal found 3/20$117
This Frontier deal was found by Cheapflights users on 3/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 5/188:17 pm
ONT
-
SFO
Nonstop1h 38m
Frontier
Wed 5/2011:26 am
SFO
-
ONT
Nonstop1h 39m
Frontier
Deal found 3/20$125
This Frontier deal was found by Cheapflights users on 3/24. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 5/208:30 am
ONT
-
SFO
1 stop14h 34m
Frontier
Wed 5/2711:15 am
SFO
-
ONT
Nonstop1h 39m
Frontier
Deal found 3/24$128
This Frontier deal was found by Cheapflights users on 3/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 4/98:49 am
ONT
-
SFO
Nonstop1h 46m
Frontier
Tue 4/142:47 pm
SFO
-
ONT
1 stop4h 02m
Frontier
Deal found 3/20$134
This Kiwi.com deal was found by Cheapflights users on 3/25. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/2211:44 am
ONT
-
SFO
1 stop7h 01m
Frontier
Wed 4/292:47 pm
SFO
-
ONT
1 stop17h 37m
Frontier
Deal found 3/25$136
This CheapOair deal was found by Cheapflights users on 3/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 4/309:10 am
ONT
-
SFO
Nonstop1h 40m
Frontier
Mon 5/46:13 pm
SFO
-
ONT
1 stop21h 31m
Frontier
Deal found 3/20$139
This Frontier deal was found by Cheapflights users on 3/24. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 4/2511:44 am
ONT
-
SFO
1 stop7h 01m
Frontier
Mon 4/279:20 pm
SFO
-
ONT
1 stop13h 24m
Frontier
Deal found 3/24$140
This Frontier deal was found by Cheapflights users on 3/24. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/1511:44 am
ONT
-
SFO
1 stop7h 01m
Frontier
Sat 4/182:47 pm
SFO
-
ONT
1 stop4h 02m
Frontier
Deal found 3/24$141
This Frontier deal was found by Cheapflights users on 3/24. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 5/98:17 pm
ONT
-
SFO
Nonstop1h 38m
Frontier
Tue 5/1211:26 am
SFO
-
ONT
Nonstop1h 39m
Frontier
Deal found 3/24$142
This Frontier deal was found by Cheapflights users on 3/24. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 4/239:10 am
ONT
-
SFO
Nonstop1h 40m
Frontier
Thu 4/232:09 pm
SFO
-
ONT
1 stop5h 55m
Frontier
Deal found 3/24$144

Find flight deals from Ontario to Fremont

Keep the following information in mind while searching for Ontario to Fremont flight deals. Data was last updated March 25, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$116
(Frontier)

One-way from

$64
(CheapOair)

Popular in

February

Cheapest in

May

Average price

$186
Provider with most accurate pricing for Los Angeles Los Angeles-San Francisco flight deals.
Search Deals
Provider most trusted by Cheapflights users for Los Angeles Los Angeles-San Francisco flights.
Search Deals
From Ontario to Fremont
Search Deals
One-way flight from Ontario to Fremont
Search Deals
Highest demand for flights based on searches. 29% potential increase in price ($74 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 6% potential price decrease ($12 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in March 2026
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Ontario to Fremont that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated March 25, 2026.
Use the filters below to find and compare flights from Ontario to Fremont that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Tue 4/21

2:10 pm-10:45 pm

2 stops8h 35m

San Francisco

Tue 4/28

2:50 pm-10:10 pm

2 stops7h 20m

$186

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Thu 4/16

11:05 am-12:35 pm

Nonstop1h 30m

San Francisco

Mon 4/20

4:10 pm-5:47 pm

Nonstop1h 37m

$249

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Wed 4/15

2:10 pm-10:45 pm

2 stops8h 35m

San Francisco

Sat 4/18

5:00 am-11:05 am

2 stops6h 05m

$257

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Fri 4/24

3:00 pm-10:10 pm

2 stops7h 10m

San Francisco

Mon 4/27

3:00 pm-11:05 pm

2 stops8h 05m

$265

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Sat 4/25

6:00 am-7:29 am

Nonstop1h 29m

San Francisco

Mon 4/27

8:25 am-9:56 am

Nonstop1h 31m

$286
Quickest round-trip

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Wed 4/22

11:05 am-12:34 pm

Nonstop1h 29m

San Francisco

Fri 4/24

10:50 am-12:20 pm

Nonstop1h 30m

$287

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Sun 4/19

6:00 am-7:29 am

Nonstop1h 29m

San Francisco

Mon 4/20

10:50 am-12:20 pm

Nonstop1h 30m

$298

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Tue 4/21

11:05 am-12:35 pm

Nonstop1h 30m

San Francisco

Wed 4/29

10:50 am-12:20 pm

Nonstop1h 30m

$309

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Wed 4/22

1:27 pm-2:56 pm

Nonstop1h 29m

San Francisco

Tue 4/28

10:50 am-12:20 pm

Nonstop1h 30m

$309

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Sun 5/3

5:15 am-10:15 am

1 stop5h 00m

San Francisco

Mon 5/4

4:05 pm-11:05 pm

2 stops7h 00m

$343

Flights are sorted by cheapest round-trip flights first.

Deals found on 3/23

Showing 1-10 of 23 resultsSorted by cheapest first
1
2
3

Best time to book a flight from Ontario to Fremont

Have a flexible travel schedule? Discover the best time to fly to Fremont 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.

Cheapflights Insights

Everything you need to know about your flight from Ontario to Fremont

How far ahead should I book a flight from Ontario to Fremont?

Use this chart to determine the optimal time to book a round-trip flight from Ontario to Fremont. Price data was last updated on March 13, 2026.

The best time to book flights from Ontario to Fremont is 74 days before your desired departure date. The cost of your flight will likely increase significantly if you book two weeks in advance of your flight.

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

Currently, May is the cheapest month in which you can book a flight from Ontario to Fremont (average of $33). Flying from Ontario to Fremont in November is currently the most expensive (average of $62). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from ONT to FR8?

Find hourly flight availability from Ontario to Fremont. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated March 25, 2026.

When flying from Ontario to Fremont, the time of day you fly usually plays a role in the price. Save by searching for a flight in the evening, which can drop the price by up to 23% versus a flight in the afternoon.

What is the cheapest day to fly from Ontario to Fremont?

Use this chart to determine the cheapest time to fly round-trip from Ontario to Fremont. Price data was last updated on March 23, 2026.

Travelers seeking maximum savings on their Ontario to Fremont flight should consider departing on Saturday evenings when fares are most often at their lowest. Sunday afternoons flights should be avoided if possible as fares are typically the most expensive at this time.

Reviews of airlines servicing Fremont

Get insights into the airlines that provide service to Fremont. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Fremont. Reviews last updated March 25, 2026.
Get a feel of what it's like to fly with Southwest,Alaska Airlines, andUnited Airlines from Ontario to Fremont by reading reviews from past customers. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.0
Very good
4,332 reviews

Entertainment

7.5

Crew

8.6

Overall

8.0

Boarding

8.1

Comfort

8.0

Food

7.0

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
4,332 reviews
Southwest
8.0
Very good
4,332 reviews

Entertainment

7.5

Crew

8.6

Overall

8.0

Boarding

8.1

Comfort

8.0

Food

7.0

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
12,108 reviews
Southwest
8.0
Very good
4,332 reviews

Entertainment

7.5

Crew

8.6

Overall

8.0

Boarding

8.1

Comfort

8.0

Food

7.0

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
9,478 reviews
Southwest
8.0
Very good
4,332 reviews

Entertainment

7.5

Crew

8.6

Overall

8.0

Boarding

8.1

Comfort

8.0

Food

7.0

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
3,017 reviews
Southwest
8.0
Very good
4,332 reviews

Entertainment

7.5

Crew

8.6

Overall

8.0

Boarding

8.1

Comfort

8.0

Food

7.0

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.

Related info for your journey

Find useful and relevant information for your journey from Ontario to Fremont. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • What airport do you fly from for flights from Ontario to Fremont?

    Located just 3.1 mi from the city center, Ontario is the airport most travelers will use when flying to Fremont from Ontario. Booking flights from Ontario (ONT) to Fremont should be relatively easy as there are 5 daily outbound flights to Fremont from 4 different airlines.

  • How popular is this Ontario to Fremont flight route?

    Within the past month, 107 users have taken a look at flights from Ontario to Fremont.

  • How long is the flight from Ontario to Fremont?

    Departing from Ontario to Fremont will take you 1h 30m. Airlines will cover a distance of 363 mi. Both multi-stop and nonstop flights can be found to your destination and back.

  • What are the cheapest airlines to fly from Ontario to Fremont one-way?

    $32 is the cheapest one-way deal found within the past few days, from Frontier. You may also be able to find cheap deals on United Airlines and Delta, with prices starting from $38 and $51, respectively.

  • What are the most reliable airlines from Ontario to Fremont?

    No one likes to see their flight delayed. When booking a flight from Ontario to Fremont consider choosing Frontier (100%), Volaris (100%) or SkyWest Airlines (92%) as they are the most reliable in getting you off to your destination on time.

  • What are the cheapest flights from Ontario to Fremont?

    Looking for the cheapest flight from Ontario to Fremont? While on average our users pay $655, our data indicates the cheapest price to be $66. The most popular route (Ontario - San Francisco), is priced around $117.

  • Can I find deals for flights from Ontario to Fremont that include hotel bookings?

    Yes. In addition to deals on Ontario to Fremont flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Ontario to Fremont?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Ontario to Fremont.

  • Can I find deals for business class flights from Ontario to Fremont?

    Yes. Cheapflights offers flight deals from Ontario to Fremont by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

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

    Currently, May is the cheapest month in which you can book a flight from Ontario to Fremont (average of $33). Flying from Ontario to Fremont in November is currently the most expensive (average of $62). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

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.

Alternative routes for Ontario to Fremont

See prices for flight routes from nearby airports that may be better suited for you.
San Francisco to Las Vegas flights
San Francisco to Los Angeles flights
Los Angeles to San Francisco flights
San Francisco to Ontario flights
Ontario to San Francisco flights
Los Angeles to Las Vegas flights
San Francisco to Santa Ana flights
San Jose to Las Vegas flights
San Francisco to San Diego flights
Burbank to Las Vegas flights
San Jose to Los Angeles flights
Santa Ana to San Francisco flights
San Diego to Las Vegas flights
Los Angeles to San Jose flights
Ontario to Las Vegas flights
Santa Ana to Las Vegas flights
Sacramento to Las Vegas flights
San Diego to San Francisco flights
Los Angeles to Sacramento flights
Oakland to Las Vegas flights
San Francisco to Burbank flights
San Francisco to Palm Springs flights
San Jose to San Diego flights
Sacramento to Los Angeles flights
Ontario to San Jose flights
Burbank to San Francisco flights
Las Vegas to Los Angeles flights
Las Vegas to San Francisco flights
Fresno to Las Vegas flights
San Jose to Santa Ana flights
Los Angeles to Reno flights
Las Vegas to Ontario flights
Santa Ana to San Jose flights
Santa Rosa to Las Vegas flights
Oakland to San Diego flights
Sacramento to Ontario flights
Sacramento to San Diego flights
Stockton to Las Vegas flights
San Diego to Sacramento flights
Las Vegas to Santa Ana flights
San Jose to Ontario flights
Reno to Los Angeles flights
Las Vegas to San Diego flights
Santa Ana to Sacramento flights
Las Vegas to Burbank flights
Reno to Las Vegas flights
Long Beach to San Francisco flights
Santa Rosa to San Diego flights
San Francisco to Long Beach flights
San Diego to San Jose flights

Top 4 airlines flying from Ontario to Fremont

Discover the top 4 airlines that operate flights from Ontario to Fremont. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated March 25, 2026.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$34Average$117FlexibilityNo cancel feeOn-time62%
United AirlinesCheapest$63Average$191FlexibilityNo cancel feeOn-time69%
Alaska AirlinesCheapest$78Average$173FlexibilityNo cancel feeOn-time75%
SouthwestCheapest$104Average$299FlexibilityNo cancel feeOn-time63%

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.