The engineering services provider has completed an extensive regeneration project of 9 Dock in Devonport, including maintenance and life extension and facility improvements.
The site will receive the UK Vanguard Class submarines, which are used for the UK's Continuous at Sea Deterrent defence infrastructure.
The upgraded facility will deliver the current $560m maintenance programme underway on HMS Victorious to extend the boat's operational life.
The project will also secure 1000 local jobs in the Plymouth region.
David Lockwood, Babcock CEO, said: “Supporting the Continuous at Sea Deterrent is the most important thing we do. The huge investment and increase in digital technology in this submarine facility ensures the UK has a sovereign, fit-for-purpose, deep maintenance capability now and in the future.
“Opening our Engineering & Skills building at City College Plymouth on the same day, demonstrates our commitment to securing the critical nuclear skills the UK needs to continue to deliver these vital defence programmes.”