Cheap flights from Chicago to Ontario from $125 MDW, ORD → ONT

Found recently, and the cheapest we hold

What have prices looked like?

Over 49 days, 24 Sept to 11 Nov, the cheapest return we saw each day was $145 to $229.

At $246, the cheapest return found recently is above that range.

Those were the prices on those days, not today's.

Could nearby dates be cheaper?

We hold no other 3-night return fares leaving within 3 days of 9 Dec to compare.

Every date we hold

165 fares on 11 departure dates

Which month looks cheapest?

December 2026 is the cheapest month — from $189.

Found recently, and the cheapest we hold

What have prices looked like?

Over 49 days, 24 Sept to 11 Nov, the cheapest one-way we saw each day was $75 to $135.

Those were the prices on those days, not today's.

Could nearby dates be cheaper?

We hold no other one-way fares leaving within 3 days of 25 Jan 2027 to compare.

Every date we hold

41 fares on 14 departure dates

Which month looks cheapest?

December 2026 is the cheapest month — from $99.

Return

Fares 60 to 89 days before departure were typically 13% lower than 0 to 6 days before departure.

From the cheapest return each day between 24 Sept and 11 Nov (49 days), grouped by how many days ahead the flight left; one adult in economy.

Each range covers different departure dates, so this compares typical fares, not the same trip priced twice.

Prices reflect recent searches — current fares may differ.

One-way

Fares 30 to 59 days before departure were typically 16% lower than 0 to 6 days before departure.

From the cheapest one-way each day between 24 Sept and 11 Nov (49 days), grouped by how many days ahead the flight left; one adult in economy.

Each range covers different departure dates, so this compares typical fares, not the same trip priced twice.

Prices reflect recent searches — current fares may differ.

How much is a return flight from Chicago to Ontario?

The cheapest return found recently is $246 with Southwest Airlines, 9 Dec to 12 Dec, found yesterday. The cheapest return we hold, of any age, is $189 with Frontier Airlines, 10 Dec to 8 Jan 2027, found 7 days ago. The cheapest return fare on each of 11 departure dates is usually $235 to $386.

How much is a one-way flight from Chicago to Ontario?

The cheapest one-way found recently is $125 with Frontier Airlines, 25 Jan 2027, found 3 days ago. The cheapest one-way we hold, of any age, is $99 with Frontier Airlines, 7 Dec, found 7 days ago. The cheapest one-way fare on each of 14 departure dates is usually $139 to $199.

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

December 2026 is the cheapest month for a return, from $189, 10 Dec to 8 Jan 2027, found 7 days ago. It is the cheapest month for a one-way too, from $99, 7 Dec, found 7 days ago.

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

In 49 days of prices between 24 Sept and 11 Nov, return fares 60 to 89 days before departure were typically 13% lower than 0 to 6 days before departure. One-way fares 30 to 59 days before departure were typically 16% lower than 0 to 6 days before departure.

Is there a direct flight from Chicago to Ontario?

Yes, the cheapest nonstop return found recently is $246 with Southwest Airlines, 9 Dec to 12 Dec, found yesterday. The cheapest nonstop one-way found recently is $150 with Southwest Airlines, 25 Jan 2027, found 3 days ago.

Every nonstop date from Chicago to Ontario

How long is the flight from Chicago to Ontario?

The cheapest nonstop one-way found recently, with Southwest Airlines on 25 Jan 2027, takes 4 h 25 min from Chicago Midway International Airport (MDW) to Ontario International Airport (ONT). The cheapest one-way found recently, with Frontier Airlines on 25 Jan 2027, takes 19 h 44 min with 1 stop, including a 14 h connection.

Which airlines have the cheapest flights from Chicago to Ontario?

Between 15 Nov and 1 Jun 2027, Frontier Airlines has the cheapest return on 7 of the 11 departure dates we hold, and Southwest Airlines on 4. Between 19 Nov and 8 Aug 2027, Southwest Airlines has the cheapest one-way on 6 of the 14 departure dates we hold, Frontier Airlines on 4 and Alaska Airlines on 3.