AirHint found the following cheapest return flights from Zagreb (ZAG) to Bucharest (OTP) in September 2025 (see full year).

Return flights

11 Sep - 15 Sep	Ryanair
12 Sep - 15 Sep	Ryanair
30 Sep - 02 Oct	Ryanair
30 Sep - 04 Oct	Ryanair
10 Sep - 11 Sep	Ryanair
30 Sep - 04 Oct	Croatia Airlines	direct
26 Sep - 02 Oct	Ryanair
23 Sep - 25 Sep	Ryanair
23 Sep - 27 Sep	Ryanair
15 Sep - 20 Sep	Ryanair
19 Sep - 21 Sep	Ryanair
15 Sep - 18 Sep	Ryanair
20 Sep - 25 Sep	Croatia Airlines	direct
18 Sep - 23 Sep	Croatia Airlines	direct
30 Sep - 03 Oct	Ryanair
29 Sep - 02 Oct	Ryanair
27 Sep - 04 Oct	Croatia Airlines	direct
29 Sep - 01 Oct	Ryanair
26 Sep - 03 Oct	Ryanair
27 Sep - 05 Oct	Air Serbia

Also check the deals for one-way flights from Zagreb to Bucharest 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 Zagreb to Bucharest in September from $134

Return flights