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 |
|
|
|