AirHint found the following cheapest return flights from Chicago (ORD) to Bangkok (BKK) in September 2025 (see full year).

Return flights

04 Sep - 10 Sep	United
04 Sep - 11 Sep	United
04 Sep - 16 Sep	United
08 Sep - 22 Sep	United
02 Sep - 23 Sep	United
08 Sep - 15 Sep	United
29 Sep - 06 Oct	United
01 Sep - 10 Sep	ANA
01 Sep - 09 Sep	ANA
23 Sep - 22 Oct	ANA
01 Sep - 11 Sep	ANA
22 Sep - 30 Sep	Cathay Pacific
28 Sep - 12 Oct	ANA
29 Sep - 14 Oct	Delta

Also check the deals for one-way flights from Chicago to Bangkok in September.

The deals are updated regularly. The prices may go up as tickets are purchased by other travellers. Only the cheapest flights are offered. Select a price to book and secure these cheap prices.

Book a cheap hotel in Bangkok

Cheap car rent in Bangkok

Cheapest return flights from Chicago to Bangkok in September from 594€

Return flights