Cheap Flights from Ontario International to Philadelphia International

Compare Ontario International to Philadelphia International flight deals

Find the cheapest month or even day of the year to fly to Philadelphia International

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Flight deals from Ontario International to Philadelphia International

Looking for a cheap last-minute deal or the best return flight from Ontario International Airport to Philadelphia International Airport? If you want to travel next month, return fares start from $357. Find the lowest prices on one-way and return tickets right here.

Philadelphia.$323 per passenger.Departing Sat, 16 May, returning Sat, 23 May.Return flight with Frontier Airlines.Outbound indirect flight with Frontier Airlines, departs from Ontario International on Sat, 16 May, arriving in Philadelphia International.Inbound indirect flight with Frontier Airlines, departs from Philadelphia International on Sat, 23 May, arriving in Ontario International.Price includes taxes and charges.From $323, select.

Philadelphia.$357 per passenger.Departing Tue, 9 Jun, returning Tue, 16 Jun.Return flight with Frontier Airlines.Outbound indirect flight with Frontier Airlines, departs from Ontario International on Tue, 9 Jun, arriving in Philadelphia International.Inbound indirect flight with Frontier Airlines, departs from Philadelphia International on Tue, 16 Jun, arriving in Ontario International.Price includes taxes and charges.From $357, select.

Philadelphia.$366 per passenger.Departing Thu, 28 May, returning Tue, 2 Jun.Return flight with Frontier Airlines.Outbound indirect flight with Frontier Airlines, departs from Ontario International on Thu, 28 May, arriving in Philadelphia International.Inbound indirect flight with Frontier Airlines, departs from Philadelphia International on Tue, 2 Jun, arriving in Ontario International.Price includes taxes and charges.From $366, select.

Philadelphia.$389 per passenger.Departing Wed, 26 Aug, returning Wed, 2 Sep.Return flight with Southwest Airlines.Outbound indirect flight with Southwest Airlines, departs from Ontario International on Wed, 26 Aug, arriving in Philadelphia International.Inbound indirect flight with Southwest Airlines, departs from Philadelphia International on Wed, 2 Sep, arriving in Ontario International.Price includes taxes and charges.From $389, select.

Philadelphia.$390 per passenger.Departing Tue, 7 Jul, returning Fri, 10 Jul.Return flight with Frontier Airlines.Outbound indirect flight with Frontier Airlines, departs from Ontario International on Tue, 7 Jul, arriving in Philadelphia International.Inbound indirect flight with Frontier Airlines, departs from Philadelphia International on Fri, 10 Jul, arriving in Ontario International.Price includes taxes and charges.From $390, select.

Philadelphia.$391 per passenger.Departing Thu, 30 Jul, returning Wed, 5 Aug.Return flight with Frontier Airlines.Outbound indirect flight with Frontier Airlines, departs from Ontario International on Thu, 30 Jul, arriving in Philadelphia International.Inbound indirect flight with Frontier Airlines, departs from Philadelphia International on Wed, 5 Aug, arriving in Ontario International.Price includes taxes and charges.From $391, select.

Philadelphia.$411 per passenger.Departing Tue, 1 Sep, returning Mon, 14 Sep.Return flight with Southwest Airlines.Outbound indirect flight with Southwest Airlines, departs from Ontario International on Tue, 1 Sep, arriving in Philadelphia International.Inbound indirect flight with Southwest Airlines, departs from Philadelphia International on Mon, 14 Sep, arriving in Ontario International.Price includes taxes and charges.From $411, select.

Philadelphia.$426 per passenger.Departing Thu, 13 Aug, returning Wed, 19 Aug.Return flight with Southwest Airlines.Outbound indirect flight with Southwest Airlines, departs from Ontario International on Thu, 13 Aug, arriving in Philadelphia International.Inbound indirect flight with Southwest Airlines, departs from Philadelphia International on Wed, 19 Aug, arriving in Ontario International.Price includes taxes and charges.From $426, select.

Philadelphia.$438 per passenger.Departing Tue, 27 Oct, returning Tue, 3 Nov.Return flight with United.Outbound indirect flight with United, departs from Ontario International on Tue, 27 Oct, arriving in Philadelphia International.Inbound indirect flight with United, departs from Philadelphia International on Tue, 3 Nov, arriving in Ontario International.Price includes taxes and charges.From $438, select.

Philadelphia.$447 per passenger.Departing Sat, 26 Sep, returning Sat, 3 Oct.Return flight with United.Outbound indirect flight with United, departs from Ontario International on Sat, 26 Sep, arriving in Philadelphia International.Inbound indirect flight with United, departs from Philadelphia International on Sat, 3 Oct, arriving in Ontario International.Price includes taxes and charges.From $447, select.

Philadelphia.$519 per passenger.Departing Fri, 13 Nov, returning Tue, 17 Nov.Return flight with Delta.Outbound indirect flight with Delta, departs from Ontario International on Fri, 13 Nov, arriving in Philadelphia International.Inbound indirect flight with Delta, departs from Philadelphia International on Tue, 17 Nov, arriving in Ontario International.Price includes taxes and charges.From $519, select.

Philadelphia.$519 per passenger.Departing Tue, 30 Jun, returning Fri, 10 Jul.Return flight with Frontier Airlines.Outbound indirect flight with Frontier Airlines, departs from Ontario International on Tue, 30 Jun, arriving in Philadelphia International.Inbound indirect flight with Frontier Airlines, departs from Philadelphia International on Fri, 10 Jul, arriving in Ontario International.Price includes taxes and charges.From $519, select.

Philadelphia.$544 per passenger.Departing Wed, 17 Jun, returning Thu, 13 Aug.Return flight with Southwest Airlines.Outbound indirect flight with Southwest Airlines, departs from Ontario International on Wed, 17 Jun, arriving in Philadelphia International.Inbound indirect flight with Southwest Airlines, departs from Philadelphia International on Thu, 13 Aug, arriving in Ontario International.Price includes taxes and charges.From $544, select.

Philadelphia.$590 per passenger.Departing Fri, 16 Oct, returning Sat, 17 Oct.Return flight with Southwest Airlines.Outbound indirect flight with Southwest Airlines, departs from Ontario International on Fri, 16 Oct, arriving in Philadelphia International.Inbound indirect flight with Southwest Airlines, departs from Philadelphia International on Sat, 17 Oct, arriving in Ontario International.Price includes taxes and charges.From $590, select.

Philadelphia.$628 per passenger.Departing Tue, 17 Nov, returning Sun, 6 Dec.Return flight with Southwest Airlines.Outbound indirect flight with Southwest Airlines, departs from Ontario International on Tue, 17 Nov, arriving in Philadelphia International.Inbound indirect flight with Southwest Airlines, departs from Philadelphia International on Sun, 6 Dec, arriving in Ontario International.Price includes taxes and charges.From $628, select.

Philadelphia.$734 per passenger.Departing Fri, 22 May, returning Sat, 15 Aug.Return flight with Southwest Airlines.Outbound indirect flight with Southwest Airlines, departs from Ontario International on Fri, 22 May, arriving in Philadelphia International.Inbound indirect flight with Southwest Airlines, departs from Philadelphia International on Sat, 15 Aug, arriving in Ontario International.Price includes taxes and charges.From $734, select.

Find the cheapest month to fly from Ontario International to Philadelphia International

We’re always keeping an eye on fares, so you can find the best one in seconds. It looks like Ontario International to Philadelphia International flights are currently cheapest in May.

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Ontario International to Philadelphia International: Alternative routes

Compare routes from Ontario International to Philadelphia below. You may find an airport to fly into that's cheaper, faster, or easier than Philadelphia International.

Ontario to Philadelphia: Flight information

The things to know before you go.

Cheapest flight found	$323
Cheapest month to fly	May

Finding cheap flights from Ontario International to Philadelphia International: Frequently asked questions

How much are return flights from Ontario International to Philadelphia International?

The best price we found for a return flight from Ontario International to Philadelphia International is $323. This is an estimate based on information collected from different airlines and travel providers over the last 4 days and is subject to change and availability.

Which airlines fly direct from Ontario International to Philadelphia International?

Currently, there are no airlines that fly direct from Ontario International to Philadelphia International. But we found flights with one or more stops from $323.

How many flights are there a week from Ontario International to Philadelphia International?

As of May 2026, there are no flights flying from Ontario International to Philadelphia International.

When is the cheapest time to fly from Ontario International to Philadelphia International?

The cheapest month to fly from Ontario International to Philadelphia International is usually May.

Which upcoming date is cheapest to fly from Ontario International Airport to Philadelphia International Airport on?

After crunching the numbers on our flight calendar, we found that it's currently cheapest to fly from Ontario International Airport to Philadelphia International Airport on Saturday, 16 May 2026.

Can I get a direct flight from Ontario International Airport to Philadelphia International Airport?

No airlines currently offer direct flights between Ontario International Airport and Philadelphia International Airport. Most routes have one or more stops.

How can I find the best flight deal to Philadelphia International?

We show every price from over 1,200 airlines and travel agents, comparing them all so you don’t have to. If you know you want to fly to Philadelphia International but you’re not ready to book, set up a Price Alert. We’ll track prices for you, and let you know when they rise or fall.

When is the best time to book flights to Philadelphia?

We crunched all the numbers in our flight calendar and it looks like the cheapest time to book a flight to Philadelphia is around 40 days in advance, so don’t leave your flight to the last minute.

Which is the cheapest airline to fly from Ontario International Airport to Philadelphia International with?

Currently, Frontier Airlines offers the cheapest flight tickets to Philadelphia International.

Flying from Ontario International Airport (ONT) to Philadelphia International Airport (PHL): what you need to know

The timezone in Philadelphia is UTC-4, which is three hours ahead of Ontario.
Give yourself enough time to catch your ONT to PHL flight. As a rule of thumb, arrive at least two hours before international departures and an hour ahead for domestic flights.
Flying during a peak time such as August? Public holidays and other high seasons can result in longer queues and delays at security. Play things extra safe and arrive up to four hours before international flights and two hours before a domestic departure.
If you want to add a stop to your trip, just deselect 'Direct flights only' when searching for your ticket from Ontario International Airport to Philadelphia International Airport. Here are the most popular stopovers between ONT and PHL:
- Chicago Midway International Airport
- Phoenix Sky Harbour International Airport
- Denver International Airport

How to find the cheapest flights from Ontario International Airport (ONT) to Philadelphia International Airport (PHL)

The cheapest price we've found for a one-way Ontario International Airport to Philadelphia International Airport flight is $178. A round-trip ticket right now is $323. Depending on the availability and when you book, these fares can change.
Don't leave things to the last minute. You're more likely to find cheap tickets from ONT to PHL if you book in advance. Airlines often offer some terrific early bird deals.
If you're willing to be flexible with your travel plans, use the 'Whole month' search function. It'll find the lowest price in each month when looking for your flight from Ontario International Airport to Philadelphia International Airport.
Cut down on the time spent looking for cheap flights from ONT to PHL by creating a Price Alert. We'll send you an email or notification on the app when fares go down.
Select your preferred departure and arrival times, airlines and number of stops with the filters. Alternatively, sort your results by 'Cheapest' to get the best deals on flights from Ontario International Airport to Philadelphia International Airport.

Handy information about Ontario International Airport (ONT)

ONT's address is 2900 E. Airport Drive.
83.6% of flights departing from Ontario International Airport land at their destination on schedule. With its impressive on-time stats, delays are unlikely when jetting out of ONT.
Ontario International Airport is about 6 kilometres from central Ontario. If you're ride-sharing, catching a cab or driving from the centre, it'll take 10 minutes or so to arrive, depending on the traffic.
Expect a journey time of about 1 hour 30 minutes on public transport.
Need a convenient hotel close to ONT? If you've booked an early flight from Ontario International Airport to Philadelphia International Airport, these accommodation options will put you moments from your departure gate:

Arriving at Philadelphia International Airport (PHL)

If you're arriving on a late Ontario International Airport to Philadelphia International Airport flight, nothing tops the convenience of staying close to the terminal. Collect your bags from the carousel and then be showered and resting shortly after at one of these accommodation options near PHL:
Get on the fast track to adventure by picking up a Philadelphia International Airport rental car. Grab your wheels from Dollar, Thrifty or Budget and explore beyond Philadelphia's main sights.
Lock in the best deal by reserving your vehicle from Philadelphia International Airport around three weeks in advance of your trip.

Getting from Philadelphia International Airport (PHL) to central Philadelphia

You'll find PHL at Industrial Highway and Island Road.
Philadelphia International Airport to central Philadelphia has a drive time of about 15 minutes. It's approximately 19 kilometres away.
If you're travelling by public transport, expect a journey of around 45 minutes.

When to fly to Philadelphia International Airport (PHL)

It's time to plan your dates for your flight from Ontario International Airport to Philadelphia International Airport. August is the most popular month to visit Philadelphia. If you like a more low-key vibe, go in February.
Lock in your flight from Ontario International Airport to Philadelphia International Airport for July if you want to explore Philadelphia during its warmest month. You can expect temperatures of between 18ºC and 32ºC.
Look for cheap tickets from ONT to PHL in January if you like travelling in cooler conditions. Temperatures are at their lowest then, ranging between -7ºC and 9ºC on average.

Explore more of United States

You've visited Philadelphia, now it's time to discover other parts of United States. Journey around 129 kilometres north-east to New York to check off its popular sights. From Statue of Liberty to Central Park and Empire State Building, you've got a jam-packed schedule ahead.
Boston is another favourite destination in United States and is around 434 kilometres north-east of Philadelphia. No journey is complete without visiting Freedom Trail, Museum of Fine Arts Boston and Boston Tea Party Ships & Museum.