AirHint found the following cheapest return flights from Washington (IAD) to Oslo (OSL) in September 2026 (see full year).

Return flights

03 Sep - 13 Sep	TAP
28 Sep - 05 Oct	Scandinavian Airlines
30 Sep - 07 Oct	Scandinavian Airlines
24 Sep - 01 Oct	Icelandair
27 Sep - 04 Oct	Icelandair
06 Sep - 13 Sep	Air France
08 Sep - 15 Sep	Air France
13 Sep - 20 Sep	Air France
14 Sep - 21 Sep	Air France
01 Sep - 08 Sep	Air France
02 Sep - 09 Sep	Air France
11 Sep - 18 Sep	Icelandair
18 Sep - 25 Sep	Icelandair
03 Sep - 10 Sep	Icelandair
25 Sep - 02 Oct	Air France
26 Sep - 03 Oct	Air France
29 Sep - 06 Oct	Air France

Also check the deals for one-way flights from Washington to Oslo 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 Washington to Oslo in September from $475

Return flights