AirHint found the following cheapest return flights from Seattle (SEA) to Ljubljana (LJU) in December 2025 (see full year).

Return flights

14 Dec - 22 Dec	Delta
16 Dec - 24 Dec	Delta
15 Dec - 23 Dec	Delta
24 Dec - 31 Dec	Delta
13 Dec - 21 Dec	Delta
22 Dec - 30 Dec	Lufthansa
17 Dec - 25 Dec	Lufthansa
24 Dec - 01 Jan	Lufthansa
26 Dec - 02 Jan	Lufthansa
22 Dec - 29 Dec	Lufthansa
26 Dec - 03 Jan	Lufthansa
25 Dec - 01 Jan	Air France
21 Dec - 28 Dec	KLM
25 Dec - 02 Jan	Delta
18 Dec - 26 Dec	Air France
27 Dec - 03 Jan	Turkish Airlines
27 Dec - 04 Jan	Turkish Airlines

Also check the deals for one-way flights from Seattle to Ljubljana in December.

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 Seattle to Ljubljana in December from $897

Return flights