AirHint found the following cheapest return flights from St. Louis (STL) to Madrid (MAD) in August 2025 (see full year).

Return flights

19 Aug - 26 Aug	Air Canada
11 Aug - 26 Aug	Air Canada
13 Aug - 20 Aug	United
15 Aug - 22 Aug	United
31 Aug - 07 Sep	Iberia
17 Aug - 24 Aug	Iberia
24 Aug - 31 Aug	Air Canada
25 Aug - 01 Sep	United
05 Aug - 12 Aug	United
11 Aug - 18 Aug	United
27 Aug - 03 Sep	Iberia
07 Aug - 14 Aug	Iberia
09 Aug - 16 Aug	Iberia
29 Aug - 05 Sep	United

Also check the deals for one-way flights from St. Louis to Madrid in August.

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 Madrid

Cheap car rent in Madrid

Cheapest return flights from St. Louis to Madrid in August from $639

Return flights