Four different players -- Megan Klingenberg, Ingrid Wells, Jessica McDonald and Kelley O'Hara -- scored for the Americans. O'Hara's goal was her sixth, tying her for the tournament lead with teammate Michelle Enyeart.
"Of course, we're happy to be going to the World Cup," said U.S. coach Tony DiCicco. "It's very important to win games, but I also want to play to our standard."
Canada, a 2-1 winner over Mexico in the other semifinal, also advanced. Mexico and Costa Rica meet in the third-place game with a berth at the 2008 world championships on the line. The USA faces Canada in the championship game.
June 25 in Puebla
USA 4 Costa Rica 0. Goals: Klingenberg 4, Wells 15, O'Hara 20, McDonald 44.
USA -- Naeher, Dallstream, Fountain, Marshall, Klingenberg, Edwards (Nairn, 69), Winters, Wells, Morgan (McDonald, 42), O'Hara (Washington, 46), Enyeart.
Costa Rica -- Tapia, Cruz, Malavassi, Alvarado, Ceden, Guillen (Acosta, 29), Y.Rodriguez, Betancourt (Granados, 46; Fuentes, 89), A.Rodriguez, Barquero, Venegas.