EXHIBIT 21.1 LIST OF SUBSIDIARIES OF CARRIER 1 INTERNATIONAL S.A. SUBSIDIARY ORGANIZATION Carrier 1 International GmbH Switzerland Telecommunikation Carrier 1 GmbH Austria Carrier1 Belgium SPRL Belgium Carrier1 Denmark Aps Denmark Carrier1 France Holding Sarl France Carrier1 France Sarl France Carrier1 Holding GmbH Germany Carrier1 GmbH & Co. KG Germany Carrier1 Beteiligungs GmbH Germany Carrier1 Fiber Network Beteiligungs GmbH Germany Carrier1 Fiber NetworkGmbH & Co. oHG Germany Carrier1 UK Ltd. Great Britain Carrier1 Italia Srl Italy Carrier1 International Management S.A. Luxembourg Carrier1 B.V. The Netherlands Carrier1 Nordics AB Sweden Carrier1 Networks GmbH Switzerland Carrier1, Inc. Delaware, United States of America