Exhibit 21.1

Significant Subsidiaries of Registrant

iBasis Securities Corporation

Mayanet LLC

iBasis Global, Inc.

iBasis Holdings, Inc.

iBasis Retail, Inc.

InkaNet, Inc.

KPN International Network Services, Inc.
iBasis Netherlands B.V
(formerly KPN Global Carrier Services B.V.)

KPN Wholesale Voice Service HK Limited

KPN Eurovoice Singapore Pte Limited

iBasis Europe Limited

iBasis Australia Pty Limited

iBasis FZ LLC

iBasis Israel Limited

iBasis Japan K.K.

iBasis Argentina SRL

iBasis Brazil Ltda.

iBasis Hong Kong Limited

iBasis Mexico S. de C.V.

iBasis Peru S.A.

iBasis Singapore Pte. Limited

Innovatel Servicos de Communicacoes Ltd.

LD Telecom S.A.C.