Cheap flights from Portland to Los Angeles from $43

In general, January is the cheapest month to fly from Portland to Ontario. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $217. If you aren’t able to travel during the month of January, then book flights to Ontario from Portland during February instead. Flights to Ontario in February, while not as cheap as those in January, still average around $222.

The cheapest day to depart on your flight to Ontario is on a Monday when prices can be found for as low as $297. This is often the case because there is less demand to fly during this day of the week. When flying out on a Tuesday, the most expensive travel day of the week, you can expect to see flight prices from Portland to Ontario for around $361.

In the evening is the cheapest time of day to fly from Portland to Ontario when you can find flight prices for as low as $304. Flying to Ontario in the evening is an ideal time because this is during off-peak travel hours. If you have a flexible travel schedule, then try to avoid flying in the morning when prices are $328 on average. Flights to Ontario from Portland in the morning are generally more expensive because this time of day is more convenient for travelers’ schedules.

Fly from Portland to Ontario for the best Portland - Ontario flight prices

You are more likely to see cheaper flights to Ontario from Portland when booking weeks ahead of your departure date. In general, you can expect to find flights to Ontario for around $307 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Ontario from Portland for as low as $229 on momondo.

There are 4 cabin classes available to choose from on Portland to Ontario flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

No. A direct flight is the cheapest option for a flight between Portland to Ontario.

As of October 2026, prices for Portland to Ontario flights are approximately 159% more expensive when compared to flights at the same time last year.

Delta, Alaska Airlines, and Southwest are the most popular carriers operating from Portland to Ontario

Alaska Airlines, Delta and Frontier are the top three most popular airlines that fly to Ontario from Portland according to our data. Alaska Airlines is the first choice among our users, with 56% of people opting to fly with this airline when traveling to Ontario. Keep in mind that there are 8 different airlines that fly to Ontario on a routine basis, so you have a few additional options to choose from.