AirHint found the following cheapest return flights from Boston (BOS) to Shannon (SNN) in August 2025 (see full year).

Return flights

25 Aug - 03 Sep	United
26 Aug - 31 Aug	United
27 Aug - 06 Sep	United
25 Aug - 01 Sep	United
25 Aug - 03 Sep	Aer Lingus	direct
14 Aug - 20 Aug	United
22 Aug - 28 Aug	Delta
30 Aug - 03 Sep	United
06 Aug - 10 Aug	United
08 Aug - 19 Aug	United
25 Aug - 01 Sep	Aer Lingus	direct
03 Aug - 07 Aug	Aer Lingus
01 Aug - 07 Aug	Aer Lingus

Also check the deals for one-way flights from Boston to Shannon 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.

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Cheapest return flights from Boston to Shannon in August from 327€

Return flights