Exhibit 8.1 MAIN SUBSIDIARIES OF TERRA NETWORKS, S.A. AT DECEMBER 31, 2004 Company Country of Incorporation - ------- ------------------------ Lycos Europe, N.V. Netherlands Terra Networks USA LLC United States Terra Networks Espana, S.A.U. Spain Terra Networks Latam, S.L. Spain Terra Networks Argentina, S.A. Argentina Terra Networks Chile, S.A. Chile Terra Networks Mexico, S.A. de C.V. Mexico Terra Networks Brasil, S.A. Brazil Terra Networks Colombia, S.A. Colombia Terra Networks Peru, S.A. Peru Terra Networks Guatemala, S.A. Guatemala Terra Networks Asociadas, S.L. Spain Azeler Automocion, S.A. Spain Iniciativas Residenciales en Internet, S.A. Spain Maptel Networks, S.A.U. Spain Ifigenia Plus, S.L. Spain Educaterra, S.A. Spain Red Universal de Marketing y Bookings Spain Online, S.A. Uno-e Bank, S.A. Spain OneTravel.com, Inc. United States