AirHint found the following cheapest return flights from Washington (IAD) to Cancun (CUN) in September 2025 (see full year).

Return flights

06 Sep - 13 Sep	United
13 Sep - 17 Sep	United	direct
13 Sep - 16 Sep	United	direct
06 Sep - 09 Sep	United	direct
30 Sep - 04 Oct	United	direct
27 Sep - 11 Oct	Aeromexico
01 Sep - 04 Sep	United
01 Sep - 05 Sep	United
20 Sep - 23 Sep	United
13 Sep - 15 Sep	United	direct
02 Sep - 16 Sep	United	direct
10 Sep - 16 Sep	United	direct
30 Sep - 07 Oct	United	direct
29 Sep - 06 Oct	Frontier Airlines
28 Sep - 05 Oct	Air Canada

Also check the deals for one-way flights from Washington to Cancun 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 Cancun

Cheap car rent in Cancun

Cheapest return flights from Washington to Cancun in September from 241€

Return flights