Barry Davis Ryan was one of three people caught up in a drowning incident last Tuesday.
They were walking close to the Beacon when one was swept into the water and the others attempted a rescue.
The bodies of Mr Ryan's girlfriend, Niamh O'Connor, 20, and his father, Barry Ryan, 51, have been recovered.
John Kearney of West Cork Underwater Search and Rescue  told RTÃ‰ there was a "weather window" on Thursday and Friday, but the weather was set to change at the weekend.
He said a very detailed search needed to be carried out and it was important that divers were experienced as the terrain is difficult and the search needs to be carried out carefully.
Mr Kearney said local fishermen were laying ground lines so that divers have a route to follow to ensure the area is "gridded completely".
Search teams in west Cork are appealing to experienced divers to assist in their search for the body of a 20-year-old man missing off Baltimore harbour.