SeaTac-based Alaska Airlines and Icelandair will end their frequent-flier alliance June 1, Alaska announced on its website Wednesday.
Icelandair tickets bought on or after June 1 won't be eligible to receive Alaska Mileage Plan credit, the airline said.
Tickets purchased on or before May 31 will continue to earn miles through the end of February next year.
Award travel booked by May 31 will be honored for travel through Feb. 28, 2014.
Award travel on Icelandair can't be booked or changed after May 31, Alaska said.
The two airline's frequent-flier breakup means flying to Europe using Alaska miles could become more difficult.
Icelandair flies from Sea-Tac to Iceland, where its flights connect with routes to nearly two dozen European cities.
Other Alaska partner airlines, including American, Delta, British, Air France and KLM, provide European flights.