AirHint found the following cheapest return flights from Denver (DEN) to Split (SPU) in September 2025 (see full year).

Return flights

02 Sep - 09 Sep	Lufthansa
29 Sep - 06 Oct	Frontier Airlines
15 Sep - 22 Sep	KLM
14 Sep - 21 Sep	Air Canada
25 Sep - 02 Oct	Frontier Airlines
24 Sep - 01 Oct	Frontier Airlines
19 Sep - 26 Sep	Frontier Airlines
20 Sep - 27 Sep	Frontier Airlines
09 Sep - 16 Sep	Lufthansa
17 Sep - 24 Sep	Frontier Airlines
03 Sep - 10 Sep	Lufthansa
30 Sep - 07 Oct	Icelandair
23 Sep - 30 Sep	Frontier Airlines
04 Sep - 11 Sep	Icelandair

Also check the deals for one-way flights from Denver to Split 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.

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Cheapest return flights from Denver to Split in September from 516€

Return flights