China Southern will withdraw from the SkyTeam Alliance on Jan. 1.
"China Southern's decision reflects its strategic development, the changing trends of the global aviation industry and the evolution of alliances," SkyTeam said in a statement Thursday.
Among SkyTeam's 20 members is competitor China Eastern. Both airlines are among China's big three carriers (along with Air China). However, China Eastern works in closer partnership with key SkyTeam members Delta and Air France-KLM than does China Southern. Delta owns 3.5% of China Eastern, and China Eastern owns 8.8% of Air France-KLM. China Eastern and Air France-KLM also jointly operate select fights under a partnership with antitrust immunity.
Conversely, China Southern codeshares with Oneworld alliance member American, which also owns 2.9% of the Guangzhou-based carrier.
SkyTeam said that it would work closely with China Southern throughout 2019 to make sure the carrier's withdrawal from the alliance is seamless.
Under airline alliances, carriers work reciprocally on lounge access, frequent flyer mileage accrual and redemption and priority check-ins. SkyTeam partners also work together on joint itineraries, allowing for baggage transfers to connecting flights as well as the sale of SkyTeam's Round the World pass.