Star Alliance’s roster of airlines will decline in the second quarter of next year when Brazilian carrier TAM joins Oneworld.

The decision by TAM’s parent company Latam Airlines Group had been expected as Chilean regulators had required that TAM not be a member of the same alliance as AviancaTaca Holdings when they approved last year’s merger between TAM and LAN Airlines.

Latam had considered leaving TAM unaligned while maintaining LAN’s relationship with Oneworld, but the parent company has instead chosen to fold its entire portfolio into Oneworld. As part of this strategy, Latam’s LAN Colombia operation will formally join the alliance by the end of 2013, and TAM’s Paraguay subsidiary will be added with its parent.

Latam says it expects TAM to join Oneworld immediately after the Brazilian carrier leaves Star.

“We evaluated all the possibilities and chose the alliance that offers the best benefits to our passengers, besides the best connectivity and products, as well as the greater synergies for Latam Airlines Group,” says CEO Enrique Cueto.

Star is not surprised by Latam’s decision, and a spokesman for the alliance notes that while TAM provided 40 Brazilian destinations, other members—namely AviancaTaca, Copa Airlines, TAP Portugal and United Airlines—already offer services to key Brazilian gateways, and that Ethiopian Airlines and South African Airlines are planning to launch their own Brazilian services.

The Star spokesman also acknowledges that the alliance “is looking into various options to secure feed to and from Brazil.”

“It definitely is something on our to-do list,” he told Aviation Week. He would not comment on possible partnerships.