AirHint found the following cheapest one-way flights from London (LHR) to Shannon (SNN) in September 2025 (see full year).

One-Way flights

15 Sep	Aer Lingus	direct
24 Sep	Aer Lingus	direct
02 Sep	Aer Lingus	direct
16 Sep	Aer Lingus	direct
17 Sep	Aer Lingus	direct
08 Sep	Aer Lingus	direct
29 Sep	Aer Lingus	direct
09 Sep	Aer Lingus	direct
22 Sep	Aer Lingus	direct
12 Sep	Aer Lingus	direct

Also check the deals for return flights from London to Shannon 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 one-way flights from London to Shannon in September from $64

One-Way flights