Exhibit 21.1

Subsidiaries of the Registrant

Acme Packet HK Ltd., a limited company organized under the laws of Hong Kong.
100% owned by Acme Packet, Inc.

Acme Packet Japan KK, a corporation organized under the laws of Japan.
100% owned by Acme Packet, Inc.

Acme Packet Securities Corp., a corporation organized under the laws of the Commonwealth of Massachusetts.
100% owned by Acme Packet, Inc.

Acme Packet UK Ltd., a limited company organized under the laws of the United Kingdom.
100% owned by Acme Packet, Inc.

Acme Packet International, Inc., a Delaware corporation.
100% owned by Acme Packet, Inc.

PAIC Midco Corp., a Delaware corporation.
100% owned by Acme Packet, Inc.

Covergence Inc., a Delaware corporation.
100% owned by PAIC Midco Corp., Inc.

Covergence HK Ltd., a limited company organized under the laws of Hong Kong
100% owned by Covergence Inc.

Acme Packet B.V. a corporation organized under the laws of the Netherlands.
100% owned by Acme Packet, Inc.

Newfound Communications, Inc., a Delaware corporation.
100% owned by Acme Packet, Inc.