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San Juan

$178+ Cheap flights from Ontario (ONT) to San Juan

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 11/18. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — SJU
Oct 11 — Oct 181
Sat 10/11
Sat 10/18
1 adult, Economy
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Cheapflights Tip: The best prices from Ontario to San Juan are usually found in October or April, booked 24 days in advance, depart on a Tuesday or Monday and return on a Wednesday

Cheap flight deals from Ontario to San Juan

Discover tips and strategies to find the most affordable flight options for your journey from Ontario (ONT) to San Juan (PR1). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated September 11, 2025.

Round-trip from

$309
(Frontier)

One-way from

$178
(Delta)

Popular in

December

Cheapest in

October

Average price

$494
From Ontario to San Juan
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One-way flight from Ontario to San Juan
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Highest demand for flights based on searches. 7% potential increase in price ($45 potential increase over avg. RT price).
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Cheapest flight prices on average. 3% potential price decrease ($21 potential savings vs. average RT price).
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Average for round-trip flights in September 2025
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Find flight deals from Ontario to San Juan

Cheapest flights from Ontario to San Juan
Explore the most affordable flight options available from Ontario to San Juan. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 11, 2025.

This Frontier deal was found by Cheapflights users on 9/10. 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.
Sun 11/97:47 amONT - SJU
2 stops13h 45mFrontier
Wed 11/129:00 amSJU - ONT
2 stops18h 50mFrontier
Deal found 9/10$309
This Kiwi.com deal was found by Cheapflights users on 9/10. 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.
Sat 10/117:04 amONT - SJU
2 stops39h 04mMultiple Airlines
Thu 10/164:04 pmSJU - ONT
1 stop27h 24mMultiple Airlines
Deal found 9/10$330
This Frontier deal was found by Cheapflights users on 9/10. 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.
Fri 10/317:44 pmONT - SJU
2 stops19h 10mFrontier
Fri 11/72:11 amSJU - ONT
2 stops12h 59mFrontier
Deal found 9/10$335
This Frontier deal was found by Cheapflights users on 9/8. 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 10/86:53 amONT - SJU
2 stops16h 37mFrontier
Wed 10/156:22 amSJU - ONT
2 stops20h 28mFrontier
Deal found 9/8$349
This Frontier deal was found by Cheapflights users on 9/10. 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 11/67:39 amONT - SJU
2 stops13h 53mFrontier
Wed 11/199:00 amSJU - ONT
2 stops18h 50mFrontier
Deal found 9/10$354
This American Airlines deal was found by Cheapflights users on 9/10. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/110:37 pmONT - SJU
1 stop19h 21mAmerican Airlines
Wed 11/57:00 amSJU - ONT
2 stops15h 20mAmerican Airlines
Deal found 9/10$355
This Frontier deal was found by Cheapflights users on 9/9. 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 10/307:44 pmONT - SJU
2 stops12h 35mFrontier
Sun 11/27:30 amSJU - ONT
2 stops15h 19mFrontier
Deal found 9/9$358
This Frontier deal was found by Cheapflights users on 9/10. 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 11/67:39 amONT - SJU
2 stops13h 53mFrontier
Wed 11/129:00 amSJU - ONT
2 stops18h 50mFrontier
Deal found 9/10$359
This Kiwi.com deal was found by Cheapflights users on 9/10. 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.
Fri 10/1011:53 amONT - SJU
2 stops29h 47mMultiple Airlines
Thu 10/164:04 pmSJU - ONT
1 stop27h 24mMultiple Airlines
Deal found 9/10$362
This Kiwi.com deal was found by Cheapflights users on 9/10. 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.
Sat 10/117:04 amONT - SJU
2 stops39h 04mMultiple Airlines
Fri 10/175:18 pmSJU - ONT
1 stop17h 31mMultiple Airlines
Deal found 9/10$369

Cheapflights Fare Finder

 
Customize your flight search to find flights from Ontario to San Juan 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 September 11, 2025.
Use the filters below to find and compare flights from Ontario to San Juan that are best for you.

Fly from

Ontario

Fly to

San Juan

Route

Depart

Return

Price

OntarioSan Juan

ONT - SJU

ONTSJU

Ontario

Wed 10/8

6:53 am-2:30 am

2 stops16h 37m

San Juan Luis Munoz Marin Intl

Wed 10/15

6:22 am-11:50 pm

2 stops20h 28m

$349

OntarioSan Juan

ONT - SJU

ONTSJU

Ontario

Wed 10/15

6:00 am-8:38 pm

1 stop11h 38m

San Juan Luis Munoz Marin Intl

Mon 10/20

1:05 am-12:13 pm

2 stops14h 08m

$373

OntarioSan Juan

ONT - SJU

ONTSJU

Ontario

Thu 9/25

3:43 pm-3:22 pm

2 stops20h 39m

San Juan Luis Munoz Marin Intl

Sat 9/27

12:28 am-3:24 pm

2 stops17h 56m

$396

OntarioSan Juan

ONT - SJU

ONTSJU

Ontario

Mon 11/17

10:25 pm-12:46 pm

1 stop10h 21m

San Juan Luis Munoz Marin Intl

Thu 12/4

1:57 pm-11:03 pm

1 stop13h 06m

$414

OntarioSan Juan

ONT - SJU

ONTSJU

Ontario

Wed 10/29

7:05 am-9:59 pm

1 stop11h 54m

San Juan Luis Munoz Marin Intl

Fri 11/7

1:46 pm-10:22 pm

1 stop12h 36m

$420

OntarioSan Juan

ONT - SJU

ONTSJU

Ontario

Tue 10/28

5:05 am-5:25 pm

1 stop9h 20m

San Juan Luis Munoz Marin Intl

Sat 11/8

8:30 am-8:44 pm

2 stops16h 14m

$445

OntarioSan Juan

ONT - SJU

ONTSJU

Ontario

Mon 10/27

5:05 am-5:25 pm

1 stop9h 20m

San Juan Luis Munoz Marin Intl

Sat 11/8

8:30 am-8:44 pm

2 stops16h 14m

$445

OntarioSan Juan

ONT - SJU

ONTSJU

Ontario

Tue 11/18

6:05 am-9:26 pm

1 stop11h 21m

San Juan Luis Munoz Marin Intl

Thu 12/4

2:25 pm-8:42 pm

1 stop10h 17m

$479

OntarioSan Juan

ONT - SJU

ONTSJU

Ontario

Sat 10/11

6:51 pm-12:00 pm

2 stops14h 09m

San Juan Luis Munoz Marin Intl

Wed 10/15

1:05 am-12:13 pm

2 stops14h 08m

$479

OntarioSan Juan

ONT - SJU

ONTSJU

Ontario

Sat 10/11

10:56 pm-12:58 pm

1 stop11h 02m

San Juan Luis Munoz Marin Intl

Fri 10/17

1:25 pm-9:29 pm

1 stop11h 04m

$518

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/10

Showing 1-10 of 22 results
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Best time to book a flight from Ontario to San Juan

Have a flexible travel schedule? Discover the best time to fly to San Juan 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 San Juan

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

Use this chart to determine the optimal time to book a round-trip flight from Ontario to San Juan. Price data was last updated on August 29, 2025.

To ensure you get the cheapest price possible for a flight from Ontario to San Juan, you should look to book at least 24 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 to San Juan?

Currently, September is the cheapest month in which you can book a flight from Ontario to San Juan (average of $254). Flying from Ontario to San Juan in June is currently the most expensive (average of $339). 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 SJU?

Find hourly flight availability from Ontario to San Juan. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated September 11, 2025.

One of the essential ways to save on airfare from Ontario to San Juan is to remain as flexible as possible. Flights that are in the afternoon tend to be the most expensive. A flight in the evening could potentially save you up to 27% on airfare.

Reviews of airlines servicing San Juan

Get insights into the airlines that provide service to San Juan. 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 San Juan. Reviews last updated September 11, 2025.
Read reviews from past customers who have flown Southwest, Delta, and United Airlines from Ontario to San Juan. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.0
Very good
4,248 reviews

Boarding

8.1

Overall

8.0

Entertainment

7.5

Food

7.0

Crew

8.6

Comfort

8.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Southwest
8.0
Very good
4,248 reviews
Southwest
8.0
Very good
4,248 reviews

Boarding

8.1

Overall

8.0

Entertainment

7.5

Food

7.0

Crew

8.6

Comfort

8.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Delta
8.0
Very good
7,960 reviews
Southwest
8.0
Very good
4,248 reviews

Boarding

8.1

Overall

8.0

Entertainment

7.5

Food

7.0

Crew

8.6

Comfort

8.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
United Airlines
7.4
Good
8,937 reviews
Southwest
8.0
Very good
4,248 reviews

Boarding

8.1

Overall

8.0

Entertainment

7.5

Food

7.0

Crew

8.6

Comfort

8.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
American Airlines
7.2
Good
10,000 reviews
Southwest
8.0
Very good
4,248 reviews

Boarding

8.1

Overall

8.0

Entertainment

7.5

Food

7.0

Crew

8.6

Comfort

8.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Frontier
5.8
Fair
3,177 reviews
Southwest
8.0
Very good
4,248 reviews

Boarding

8.1

Overall

8.0

Entertainment

7.5

Food

7.0

Crew

8.6

Comfort

8.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.

Related info for your journey

Find useful and relevant information for your journey from Ontario to San Juan. 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 San Juan?

    If you book a flight to San Juan from Ontario, you will be flying from Ontario, which is the city’s only airport. Ontario (ONT) is located 3.1 mi from the center of Ontario. There are 0 flights from Ontario to San Juan per day from 5 different airlines.

  • How long is the flight from Ontario to San Juan?

    Airlines like Frontier, United Airlines, and Delta fly from Ontario to San Juan in about 10h 21m. The time it takes to get you to your destination can typically vary by up to 6h 16m. Airlines will cover a distance of 3334 mi. This flight may include one or multiple stops.

  • What are the cheapest airlines flying from Ontario to San Juan round-trip?

    Frontier, at $73, was found to be the cheapest airline from Ontario to San Juan.Alternate airlines to your destination round-trip include Delta and American Airlines. Frontier is currently priced 87% below the average price you’ll pay for this route.

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

    $178 is the cheapest one-way deal found within the past few days, from Delta. You may also be able to find cheap deals on JetBlue and Frontier, with prices starting from $190 and $198, respectively.

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

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

  • How can I find direct flights from Ontario to San Juan?

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

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

    Yes. Cheapflights offers flight deals from Ontario to San Juan 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 San Juan?

    Currently, September is the cheapest month in which you can book a flight from Ontario to San Juan (average of $254). Flying from Ontario to San Juan in June is currently the most expensive (average of $339). 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

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Top 5 airlines flying from Ontario to San Juan

Discover the top 5 airlines that operate flights from Ontario to San Juan. 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 September 11, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$73Average$467FlexibilityNo cancel feeOn-time62%
DeltaCheapest$355Average$534FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$365Average$608FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$366Average$589FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$409Average$572FlexibilityNo cancel feeOn-time63%

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