AirHint found the following cheapest return flights from Kolkata (CCU) to London (LHR) in September 2025 (see full year).

Return flights

21 Sep - 23 Sep	Etihad Airways
25 Sep - 10 Oct	Etihad Airways
18 Sep - 23 Sep	Air India
18 Sep - 24 Sep	Air India
23 Sep - 30 Sep	Air India
16 Sep - 30 Sep	Air India
23 Sep - 01 Oct	Air India
23 Sep - 02 Oct	Air India
30 Sep - 06 Oct	Air India
25 Sep - 30 Sep	Air India
09 Sep - 25 Sep	Air India
30 Sep - 09 Oct	Air India
17 Sep - 10 Oct	Air India
09 Sep - 19 Sep	Air India
09 Sep - 28 Sep	Air India
25 Sep - 02 Oct	Air India
26 Sep - 07 Oct	Air India
25 Sep - 05 Oct	Air India
26 Sep - 02 Oct	Air India
12 Sep - 26 Sep	Air India

Also check the deals for one-way flights from Kolkata to London 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.

Book a cheap hotel in London

Cheap car rent in London

Cheapest return flights from Kolkata to London in September from $631

Return flights