About 110 boats, including civilian vessels, took part in the search for Paul Ormsby and Ciarán Smith.
The co-ordinated search took place along the Irish west coast on Saturday.
Both men have been missing since Irish Coast Guard helicopter Rescue 116 crashed off on 14 March.
Four people were on board the helicopter when it came down off the County Mayo coast.
Capt Dara Fitzpatrick died after she was rescued from the sea hours after the crash.
The body of her co-pilot, Capt Mark Duffy, was later recovered from the wreckage.
Last Sunday, the wreckage of the helicopter was lifted from where it crashed near Blackrock Island but the two missing crew members were not found.
Saturday's search involved the Irish Coast Guard, RNLI, Irish Air Corps, Irish Naval Service and Irish Civil Defence, along with more than 80 civilian boats.
However, the extensive search, which stretched over hundreds of square miles from County Donegal to County Mayo, failed to find any sign of the two men.
Inshore boats worked close to the coastline and larger vessels further out to sea.
Helicopters searched from the air while a shoreline effort was assisted by search and rescue volunteers from across the Republic and Northern Ireland.
Search teams from Counties Down, Wicklow, Dublin, Donegal, Claire and Tipperary were among those who took part.
The search came days after an appeal from a sister of Ciarán Smith for help from fishermen and coastal communities in searching for the men.
Speaking after the search, Orla Smith said the support show by the fishing communities had given the families renewed hope and that there were no words to thank those involved in the search.
An investigation into what happened to the helicopter is continuing.
The Air Accident Investigation Unit has said there was no indication of any mechanical problems in the seconds before the impact.
It is thought the inquiry into the cause of the crash on 14 March will now focus on operational issues.
A major sea search described as one of the biggest in Irish state history has failed to locate two Irish Coast Guard crew members missing since a helicopter crash.