The divers disappeared when they had been exploring the HMS Scylla which was sunk in 2004 to create a reef.
Emergency services were alerted at 7:45pm on Friday by a member of the diving party when the two divers didn’t return to the surface.
Search operations pushed on until the early hours of Saturday morning near Whitsand Bay.
Divers have been advised to avoid the area at this time.
James Instance from Falmouth Coastguard said the pair are feared to be dead but this hasn’t been confirmed.
Mr Instance said: “We swang into action a search and rescue plan involving the rescue helicopter from Newquay, the Looe and Plymouth inshore lifeboats, Plymouth all-weather lifeboat, a police launch and other vessels. The dive boat also remained on scene.
“We were unable to locate or find anybody.
“Our thoughts are with the people who were in the dive party who are dealing with what is a very traumatic experience.”