The submarines, the sixth and seventh Astute class vessels of the British navy, are being built by BAE Systems Maritime-Submarines in Cumbria.
"Thales is proud to be supplying Sonar 2076 for all seven Astute class submarines," said Phil Naybour, head of Thales UK's naval business.
"This successful program reflects the skill and dedication of our teams ... and also the close support and cooperation we have received from BAE Systems and the Ministry of Defense."
The sonar system to be supplied will include both inboard and outboard bow, fin, intercept and flank arrays and inboard processing equipment.
"BAE Systems is pleased to award Thales UK these important contracts for the sonar systems for the sixth and seventh Astute class submarines," said Ian Hawkes, head of Combat Systems, BAE Systems Maritime-Submarines.
"Placing these contracts not only continues a well-established and enduring relationship with Thales UK, it also helps the submarine enterprise to meet the submarine program affordability challenge by obtaining economy of scale through batch procuring the sonar."
Thales said its involvement with the Astute class building program is not limited to sonar gear. It also supplies two non-hull penetrating CM010 optronic masts, electronic support systems and communications and emergency buoys.