Don’t sleep on Alaska.The Seattle-based airline now has codeshares on some 250 routes with various partners. Those airline allies are American, British Airways, Qatar Airways, Iberia, Cathay Pacific, Japan Airlines and Qantas.For more TPG news delivered each morning to your inbox, sign up for our daily newsletter.Now, in more good news for Alaska passengers craving international travel, Alaska Airlines and Finnair recently announced an expanded codesharing agreement that will make flying between European cities and West Coast hubs easier than ever.“By this summer, Alaska and these eight Oneworld airlines will offer more than 78 daily international flights from Seattle, Portland, San Francisco and Los Angeles, enabling seamless connectivity to Alaska’s comprehensive network up and down the West Coast,” Alaska said in a press release announcing the codeshare.Alaska jet with Oneworld livery. (Photo courtesy of Alaska Airlines)In 2021, Alaska Airlines joined the Oneworld Alliance — a coalition of 14 major international airlines that includes behemoths like British Airways, Japan Airlines and American Airlines — and since then, Alaska Airlines has rapidly expanded its codesharing partnerships. As Alaska Airlines senior executive Nat Pieper explains, “We joined Oneworld for the opportunity to expand partnerships with world-class airlines such as Finnair. This agreement will offer its customers and our guests’ amazing travel possibilities.“Alaska Airlines and Finnair boast the most seamless networks across the West Coast and Europe, respectively, and the new partnership will drastically increase the number of flights from cities like Portland, Seattle, Los Angeles and San Francisco to major European destinations.Seattle. (Photo by Caroline Tanner/The Points Guy)For those unfamiliar with airline jargon, the terms “codesharing” and “airline alliances” bear explaining. Put simply, codesharing refers to the practice of sharing routes among airlines. Let’s use the upcoming Alaska Airlines-Finnair partnership to illustrate: Once the agreement is in full effect, you will be able to book Alaska Airlines flights between West Coast hubs and European capitals with a connection in Helsinki, Finland’s capital and Finnair’s hometown airport. The second leg of the trip from Helsinki would be on a Finnair flight, but you could book the whole trip through Alaska Airlines and earn Mileage Plan miles for both legs of the itinerary. This article by TPG writer Ben Smithson further details how codesharing works and why airlines do it.Helsinki, Finland (Finn stock/Shutterstock)Airline alliances are partnerships between major airlines that grant travelers such perks as the ability to transfer and redeem points between member airlines and enjoy elite status benefits across the alliance. There are three major airline alliances, which are, in order of largest to smallest, Star Alliance, SkyTeam and Oneworld. Almost all major international airlines are part of one of these three alliances, with the notable exceptions of Virgin Australia and Etihad — two major airlines that roll solo.Sign up for our daily newsletterEmail addressSign upI would like to subscribe to The Points Guy newsletters and special email promotions. The Points Guy will not share or sell your email. See privacy policy.So, since Alaska and Finnair are both members of the Oneworld Alliance, you can transfer and redeem points between the two airlines. Better yet, if you have Alaska Airlines’ elite status, you would be eligible for upgrades on Finnair flights and get bonuses like free checked bags and priority check-in. To dive deeper into the nuances of airline alliances, check out this article.In addition to expanded codesharing with Finnair, Alaska Airlines also codeshares with major Asian airlines like Japan Airlines and Hong Kong-based Cathay Pacific. Travelers can access up to 1,000 different destinations through Alaska Airlines. With enough Alaska Airlines miles, the possibilities for globetrotting are endless. Want to visit Tokyo or Doha? The new partnership “will bring the Continent and much of the West Coast closer together,” notes Pieper. In short, the new agreement between Alaska Airlines and Finnair will bring that Paris vacation or crazy post-pandemic week in Berlin just a little closer to realization.It’s not all good news for Alaska customers.As we’ve been reporting Alaska has made some pretty-unfriendly customer moves recently. That includes making award availability on partner airlines harder to find and more expensive, raising prices for awards in first-class, adding dynamic pricing on some award tickets and cutting mileage earnings with some partners.