AirHint found the following cheapest return flights from Belfast (BFS) to Dublin (DUB) in September 2025 (see full year).

Return flights

15 Sep - 18 Sep	easyJet
15 Sep - 22 Sep	Ryanair
01 Sep - 04 Sep	Ryanair
02 Sep - 05 Sep	Ryanair
19 Sep - 21 Sep	Ryanair
16 Sep - 19 Sep	easyJet
09 Sep - 10 Sep	easyJet
18 Sep - 22 Sep	easyJet
24 Sep - 24 Sep	easyJet
05 Sep - 07 Sep	Ryanair
28 Sep - 05 Oct	easyJet

Also check the deals for one-way flights from Belfast to Dublin 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 Belfast to Dublin in September from 106€

Return flights