How far in advance should I book a flight from Guam to Ontario?

When searching for a good deal, it’s best to be prepared for potential fluctuations in price. We recommend booking at least 28 days in advance, which can save you up to 22% on flights from Guam to Ontario compared to booking the week you need them. Waiting 28 days out may not be for everyone, so we have options available for flights within the next two weeks, with the lowest price starting at $1,627. For sooner than that we have options available in the next 3 days from $1,901.

What is the cheapest month to fly from Guam to Ontario?

Flights from Guam to Ontario lean towards being more expensive in December. Prices are generally better when you fly from Guam to Ontario in October, with the cheapest ticket starting at $1,359.

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

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Guam to Ontario as you normally would.

What airport do you fly into for flights to Ontario from Guam?

For a flight from Guam to Ontario, you will be flying into Ontario. Ontario (ONT) is just 3.1 mi from the center of the city.

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

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

How can I find direct flights from Guam to Ontario?

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

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

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

$1,554+ Flights from Guam to Ontario - Compare & Save Big

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Cheap flight deals from Guam to Ontario

Most accurate provider	AranGrant 3 stars
Most trusted provider	AranGrant 3 stars
Round-trip from	$1,534 (United Airlines)
One-way from	$1,390 (United Airlines)
Popular in	December
Cheapest in	October
Average price	$1,505

Provider with most accurate pricing for Tamuning Guam Intl-Los Angeles flight deals.

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Provider most trusted by Cheapflights users for Tamuning Guam Intl-Los Angeles flights.

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From Guam to Ontario

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One-way flight from Guam to Ontario

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Highest demand for flights based on searches. 2% potential increase in price ($43 potential increase over avg. RT price).

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Cheapest flight prices on average. 0% potential price decrease ($10 potential savings vs. average RT price).

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Average for round-trip flights in May 2025

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Find flight deals from Guam to Ontario

Cheapest flights from Guam to Ontario
Explore the most affordable flight options available from Guam to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on mayo 1, 2025.

sáb. 5/3112:30 pmGUM - ONT

2 stops27h 15mUnited Airlines

dom. 6/226:41 pmONT - GUM

2 stops30h 24mUnited Airlines

Deal found 4/29

$1,534

Best flights from Guam to Ontario
Discover carefully curated flight deals from Guam to Ontario that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated mayo 1, 2025.

sáb. 5/3112:30 pmGUM - ONT

2 stops27h 15mUnited Airlines

dom. 6/226:41 pmONT - GUM

2 stops30h 24mUnited Airlines

Deal found 4/29

$1,534

Last-minute flights from Guam to Ontario
Discover last-minute flight deals from Guam to Ontario. Data last updated mayo 1, 2025 and is based on user searches.

vie. 5/97:10 amGUM - ONT

2 stops27h 51mUnited Airlines

sáb. 5/103:10 pmONT - GUM

2 stops58h 05mUnited Airlines

Deal found 4/29

$1,964

sáb. 5/3112:30 pmGUM - ONT

2 stops27h 15mUnited Airlines

dom. 6/226:41 pmONT - GUM

2 stops30h 24mUnited Airlines

Deal found 4/29

$1,534

One-way flights from Guam to Ontario
Search for one-way flight options from Guam to Ontario. Find affordable one-way fares based on user searches. Data last updated mayo 1, 2025.

mar. 7/17:15 amGUM - ONT

2 stops22h 17mUnited Airlines

Deal found 4/28

$1,390

Cheapflights Fare Finder

Use the filters below to find and compare flights from Guam to Ontario that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

TamuningOntario

GUM - ONT

GUMONT

Tamuning Guam Intl

sáb. 5/31

12:30 pm-10:45 pm

2 stops27h 15m

Ontario

dom. 6/22

6:41 pm-6:05 pm

2 stops30h 24m

$1,534

TamuningOntario

GUM - ONT

GUMONT

Tamuning Guam Intl

mar. 7/1

7:15 am-10:52 pm

3 stops32h 37m

$1,390

Flights are sorted by cheapest round-trip flights first.

Deals found on 4/28

Best time to book a flight from Guam to Ontario

Have a flexible travel schedule? Discover the best time to fly to Ontario from Guam 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 Guam to Ontario

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

Currently, August is the cheapest month in which you can book a flight from Guam to Ontario (average of $246). Flying from Guam to Ontario in March is currently the most expensive (average of $328). 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.

Rainfall in Ontario by month

In terms of precipitation, rainfall in Ontario ranges from 0.1 - 3.4 inches per month. February is typically the wettest month, when rainfall can reach 3.4 in. June is typically the driest time to visit Ontario when rainfall is around 0.1 in.

Temperature in Ontario by month

If weather is an important factor for your trip to Ontario, use this chart to help with planning. For those seeking warmer temperatures, August is the ideal time of year to visit, when temperatures reach an average of 78.8 F. Travelers looking to avoid the cold should look outside of December, when temperatures are typically at their lowest (around 53.6 F).

Reviews of airlines servicing Ontario

United Airlines

7.4

Good

8,696 reviews

Reviews

1 / 20

4.0

Okay

Thomas,Apr 2025

TPE - SFO

The boarding experience was okay. The dietary food choices were limited, the midway snacks were hard and dry. The seat was uncomfortable - stiff seat cushion, seat back kept springing back to the upright position, narrow seat width. Love the app and the ability to track my luggage. Flight crew was efficient.

United Airlines

7.4

Good

8,696 reviews

United Airlines

7.4

Good

8,696 reviews

Reviews

1 / 20

4.0

Okay

Thomas,Apr 2025

TPE - SFO

Related info for your journey

What airport do you fly into for flights to Ontario from Guam?
For a flight from Guam to Ontario, you will be flying into Ontario. Ontario (ONT) is just 3.1 mi from the center of the city.
Can I find deals for flights from Guam to Ontario that include hotel bookings?
Yes. In addition to deals on Guam to Ontario flights, Cheapflights offers vacation packages that include both flights and hotel.
How can I find direct flights from Guam to Ontario?
After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Guam to Ontario.
Can I find deals for business class flights from Guam to Ontario?
Yes. Cheapflights offers flight deals from Guam to Ontario 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 Guam to Ontario?
Currently, August is the cheapest month in which you can book a flight from Guam to Ontario (average of $246). Flying from Guam to Ontario in March is currently the most expensive (average of $328). 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 airline flying from Guam to Ontario

Airline	Cheapest	Average	Flexibility	On-time
United Airlines	Cheapest$1,392	Average$1,648	FlexibilityNo cancel fee	On-time69%

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$1,390+ Cheap flights from Guam to Ontario (ONT)

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 7/1. Fares are subject to change and may not be available on all flights or dates of travel.

Find cheap flights from Guam to Ontario with Cheapflights

1. Tell us where you want to go

2. Select your favorite providers

3. Compare prices and book

Cheap flight deals from Guam to Ontario

Keep the following information in mind while searching for Guam to Ontario flight deals. Data was last updated mayo 1, 2025.

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Round-trip from

One-way from

Popular in

Cheapest in

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Find flight deals from Guam to Ontario

Cheapest flights from Guam to OntarioExplore the most affordable flight options available from Guam to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on mayo 1, 2025.

Explore the most affordable flight options available from Guam to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on mayo 1, 2025.

Cheapflights Fare Finder

Use the filters below to find and compare flights from Guam to Ontario that are best for you.

Best time to book a flight from Guam to Ontario

Have a flexible travel schedule? Discover the best time to fly to Ontario from Guam with our price prediction graph.

Cheapflights Insights

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

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

Rainfall in Ontario by month

Plan your trip to Ontario by taking into account the average rainfall totals by month.

Temperature in Ontario by month

Plan your trip to Ontario by taking into account the average temperature totals by month.

Reviews of airlines servicing Ontario

Related info for your journey

Find useful and relevant information for your journey from Guam to Ontario. 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 into for flights to Ontario from Guam?

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

How can I find direct flights from Guam to Ontario?

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

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

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 Guam to Ontario

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Top airline flying from Guam to Ontario

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Cheapest flights from Guam to Ontario
Explore the most affordable flight options available from Guam to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on mayo 1, 2025.