Telekom Albania

T-Systems Belgium NV

Novatel EOOD

T-Systems Nordic TC A/S

Deutsche Telekom AG / Zentrale des Konzerns
Telekom Deutschland GmbH

TSI Finnland

T-Systems France SAS

OTE (Hellenic Telecommunications Organization S.A.)
Cosmote (Cosmote Mobile Telecommunications S.A.)
T-Systems Information and Communication Technology E.P.E.

T-Systems Limited
Deutsche Telekom (UK) Ltd

T-Systems Spring Italia srl

Hrvatski Telekom d.-d.

T-Systems Luxembourg S.A.

Makedonski Telekom AD

Crnogorski Telekom A.D.

T-Mobile Netherlands B.V.
T-Systems Nederland B.V.

T-Mobile Austria GmbH
Software Daten Service Gesellschaft m.b.H.
T-Systems Austria GesmbH

T-Mobile Polska S.A.
T-Systems Polska Sp.z o.o.

Combridge S.R.L.
CosmOTE Romania
Telekom Romania Communications S.A.
T-Systems ICT Romania S.R.L.
GTS Telecom Srl

T-Systems CIS

T-Systems Schweiz AG

T-Systems Nordic TC A/S

Slovak Telekom, a.s.
T-Systems Slovakia s.r.o.

T-Systems ITC Iberia, S.A

T-Mobile Czech Republic, a.s.

T-Systems Telekomünikasyon Limited Sirketi

Novatel Ukraine LLC.

Magyar Telekom Nyrt.
IT Services Hungary Szolgáltató Kft.

T-Systems South Africa (Pty) Limited

T-Systems Information and Communication Technology India Private Limited

T-Systems Malaysia Sdn. Bhd.

T-Systems Singapore Pte. Ltd.

T-Systems P.R. China Ltd.

T-Systems Canada, Inc.

T-Systems Mexico S.A. de C.V.

T-Mobile USA, Inc.
T-Systems North America, Inc.

T-Systems Argentina S.A.

T-Systems do Brasil Ltda.