Exhibit 21.1 Subsidiaries of the Registrant As of December 31, 1998 Jurisdiction of Subsidiary Incorporation - -------------------------------------------------------------------------------- Primus Telecommunications, Inc. Delaware Primus Telecommunications International, Inc Delaware Primus Telecommunications, Ltd. United Kingdom Primus Telecommunications de Mexico, S.A. de C.V. Mexico Primus Telecommunications Pty., Ltd. Australia Primus Telecommunications (Australia) Pty., Ltd. Australia (formerly known as Axicorp Pty., Ltd.) 3362426 Canada Inc. Canada d/b/a Primus Canada Primus Telecommunications Netherlands B.V. Netherlands Primus Telecommunications SA France Primus Telecommunications Deutschland GmbH Germany Primus TeleCom A/S Denmark Primus Telecommunicaciones SA Spain Primus Telecommunications AG Switzerland Primus Telecommunications SRL Italy PremierSource International L.L.C. Delaware Primus Telecommunications K.K Japan Primus Japan K.K. Japan Eclipse Data Services Pty., Ltd. Australia Hotkey Internet Services Pty., Ltd. Australia Telepassport Network K.K. Japan Rate Reduction Center, Inc. Florida Least Cost Routing, Inc. Florida Rockwell Communications Corporation Florida Intex Telecommunications, Inc. South Carolina TresCom International, Inc. Florida TresCom Network Services, Inc. Florida TresCom U.S.A., Inc. Florida Global Telephone Holding, Inc. U.S. Virgin Islands InterIsland Telephone Corp. U.S. Virgin Islands The St. Thomas and San Juan Telephone Company, Inc. U.S. Virgin Islands STSJ Overseas Telephone Company, Inc. Puerto Rico OTC Network Assets, Inc. Puerto Rico Puerto Rico Telecom Corporation New York STSJ Network Assets, Inc. U.S. Virgin Islands