EX-21 3 adtn-ex21.htm EX-21

Exhibit 21

SUBSIDIARIES OF ADTRAN HOLDINGS, INC.

December 31, 2023

Name of Subsidiary |  | Country or State of Incorporation
ADTRAN Networks Pty. Ltd |  | Australia
ADTRAN Networks Comunicações Ltda. |  | Brazil
ADTRAN Canada, Inc. |  | Canada
ADTRAN d.o.o. |  | Croatia
ADTRAN, Inc. |  | State of Delaware
ADTRAN International, Inc. |  | State of Delaware
ADTRAN Networks Worldwide, Inc. |  | State of Delaware
ADTRAN Networks, LLC |  | State of Delaware
Bluesocket, Inc. |  | State of Delaware
ADTRAN Oy |  | Finland
ADTRAN GmbH |  | Germany
ADTRAN Networks M.E.P.E. |  | Greece
ADTRAN Networks India Private Limited |  | India
ADTRAN Holdings Ltd. |  | Israel
ADTRAN S.R.L. |  | Italy
ADTRAN Networks Sdn Bhd |  | Malaysia
ADTRAN Networks S.A. de C.V. |  | Mexico
ADTRAN Peru S.R.L. |  | Peru
ADTRAN Sp. z.o.o. |  | Poland
ADTRAN, Unipessoal Lda. |  | Portugal
ADTRAN International, Inc. - Saudi Arabia branch |  | Saudi Arabia
ADTRAN s.r.o. |  | Slovakia
ADTRAN Proprietary Ltd. |  | South Africa
ADTRAN Switzerland GmbH |  | Switzerland
ADTRAN GmbH (Tunisia Permanent Establishment Branch Office) |  | Tunisia
ADTRAN SARL |  | Tunisia
ADTRAN Europe Limited |  | United Kingdom
ADTRAN Networks and Services Egypt, LLC |  | Egypt
ADTRAN Networks New Zealand Ltd. |  | New Zealand
Adtran Networks SE |  | Germany
Adtran Networks North America, Inc. |  | State of Delaware
Adtran Networks (UK) Limited |  | United Kingdom
Oscilloquartz SA |  | Switzerland
Adtran Networks Spólka z o.o. |  | Poland
Adtran Networks Israel Ltd. |  | Israel
ADVA Optical Networking (Shenzhen) Ltd. |  | China
Oscilloquartz Finland Oy |  | Finland
ADVA IT Solutions Pvt. Ltd. |  | India
ADVA Optical Networking Trading (Shenzhen) Ltd. |  | China
Adtran Networks Singapore Pte. Ltd. |  | Singapore
Adtran Networks Hong Kong Limited |  | China
ADVA Optical Networking (India) Private Ltd. |  | India
ADVA Optical Networking Serviços Brazil Ltda. |  | Brazil
Adtran Networks Japan Co., Ltd. |  | Japan
Adtran Networks AB |  | Sweden
ADVA NA Holdings Inc. |  | State of Georgia
Adtran Networks Australia Pty Ltd. |  | Australia
Adtran Networks B.V. |  | Netherlands
Adtran Networks Canada, Inc. |  | Canada
ADVA Network Security GmbH |  | Germany