The cheapest times to fly from GUM to ONT are

  • January 22nd to March 18th (except the week of March 5th)
  • April 2nd to May 20th (except the week of May 7th)
  • August 27th to December 2nd (except the week of September 3rd)

based on data collected exclusively by Champion Traveler across tens of millions of flights. Among all the dates above, the very cheapest time to fly from GUM to ONT is mid to late September. Prices can be as high as $1900 for Saturday flights during early to mid August, or as low as $1243 for Wednesday flights around mid to late September.


When to Fly to Ontario

Flying from Guam, GU (GUM) to Ontario, CA (ONT) will usually cost between $1333 to $1635 per person if booking more than four weeks in advance. On average the very cheapest time to fly is mid to late September with an average ticket price of $1295. Due to high demand the most expensive time to fly is early to mid August, with an average price of $1572. Planning your trip to low-cost times can easily save you $278 on economy flights and even more on first-class flights. Generally, any price below $1433 can be considered a good price for a round-trip GUM to ONT flight.

See below for a graph of average weekly prices for the GUM to ONT route. All prices are for round-trip tickets in USD.

GUM to ONT Flight Prices

Compared to other flights, the GUM to ONT flight is slightly more expensive than the average and costs about as much as the average flight leaving from Guam. The average price per mile (for a direct flight) is $0.15, which is far below average.


Flight Prices by Day of the Week

Wednesday is usually the cheapest day to fly to ONT, and Tuesday the cheapest day to fly back into GUM. Saturdays are the most expensive days to fly out or take a return trip. Selecting flights on the least expensive days could save you up to $120 (6%) on this flight.

Departing prices are for round-trip flights returning on the day of departure. For example, a flight departing on Wednesday and returning a week later will cost an average of $1391. Return trip prices are from the ONT to GUM flight, and often highlight the quality of our data in showing the same trend.

Departing Prices by Day

Departure Day Prices

Return Trip Prices by Day

Return Day Prices


Nonstop Flights and Layovers

Travelers looking to fly from GUM to ONT can generally find a 1-layover flight. Because there is not usually a direct flight option the real-world direct flight time of 12 hour 0 minutes may not be realistic.


Flight Hacking GUM to ONT

Flight hacking is when you book two tickets instead of a layover, sometimes with different airlines. You will need to either bring only a carry-on bag (highly recommended) or leave yourself plenty of time to go through security again. Flight hacking is completely allowed, but airlines don’t always tell you the cheapest way to get from GUM to ONT — but Champion Traveler does!

Hack #1: Manila (GUM > MNL > ONT)

  • Price for both tickets: $1073
  • Average savings: $361 (25.16%)

See GUM to MNL flights

Hack #2: Taipei (GUM > TPE > ONT)

  • Price for both tickets: $1281
  • Average savings: $153 (10.64%)

See GUM to TPE flights

Hack #3: Seoul (GUM > ICN > ONT)

  • Price for both tickets: $1296
  • Average savings: $138 (9.6%)

See GUM to ICN flights


Flight Questions Answered

Still have questions about flying from GUM to ONT? We’ve got answers.

Which airlines fly this route?

You can find 7 major airlines flying this route most often: American, ANA, China Airlines, Delta, Hawaiian, JAL, United, and potentially more during busy seasons.

How far away is it from Ontario International Airport to Guam International Airport?

The distance between the two airports is roughly 6122 miles or 9852 kilometers.

How long does it take to fly from GUM to ONT?

The real-world flight time for a nonstop GUM to ONT flight is about 12 hour 0 minutes.

How many flights go between Guam, GU and Ontario, CA?

It depends on the day of the week and the date, but a typical day might have around 18 available flights from GUM to ONT.


Airport Location Info


Departing Airport

Origination code GUM
Origination airport name Guam International Airport
City Guam, GU
Country the United States
Latitude 13.5
Longitude 144.8

Return Airport

Destination code ONT
Destination airport name Ontario International Airport
City Ontario, CA
Country the United States
Latitude 34.1
Longitude -117.6


Other Resources

Please note that while we’ve worked hard to analyzed tens of millions of flights to get you this data, we do not calculate current live prices or guarantee pricing. Please see our partners using the links above for current offers.