Chicago to Ontario in September 2026

Dated one-way fares from Chicago to Ontario in September 2026. Use the calendar to see which days are cheaper.

Lowest this month $95

Highest this month $142

Sample fare $95

Airports ORD–ONT

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September 2026 price calendar

From $95 · up to $142

Mon

Tue

Wed

Thu

Fri

Sat

Sun

1 $115 2 $95 3 $118 4 $118 5 $142 6 $126 7 $126 8 $126 9 $126 10 $110

Ontario ONT

$95

Sep 02, 2:41pm · 11h 9m · 1 stop

ORD → ONT · Frontier Airlines

Ontario ONT

$110

Sep 10, 6:30am · 19h 17m · 1 stop

ORD → ONT · Frontier Airlines

Ontario ONT

$115

Sep 01, 9:10pm · 13h 26m · 1 stop

ORD → ONT · Frontier Airlines

This page is only September 2026 on the Chicago to Ontario route. Open the full route if you want the next months side by side.

Prices move as seats sell. Confirm the live itinerary before you book Chicago to Ontario in September 2026.