AirHint found the following cheapest return flights from Ontario (ONT) to Keflavik (KEF) in December 2025 (see full year).

Return flights

18 Dec - 08 Jan	Alaska Airlines
29 Dec - 09 Jan	Alaska Airlines
22 Dec - 05 Jan	Alaska Airlines
20 Dec - 04 Jan	British Airways
18 Dec - 02 Jan	British Airways
18 Dec - 04 Jan	British Airways
19 Dec - 04 Jan	British Airways

Also check the deals for one-way flights from Ontario to Keflavik 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 Ontario to Keflavik in December from 866€

Return flights