Anthony and Yvonne Pardoe travelled round the world collecting the items which date from the 1900s to the 1950s.
Buyers from the US, Israel and Holland attended the auction at Bearnes, Hampton and Littlewood, Exeter.
It was thought to be "the fourth largest collection in the world" director Christopher Hampton said.
A US Navy Helium diving helmet took top price for a single item at £8,000, followed by an Italian helmet which took £7,200.
Auctioneer Brian Goodison-Blanks said: "When you start looking back and start thinking, 'well how did these guys actually go down with these diving helmets on', it looks incredible."
He said the colours and patterns of the helmets also sparked "that emotive Jules Verne feeling" in people and "just look wonderful".
A lifetime's collection of hundreds of diving helmets and equipment has fetched £476,000 at auction.