The U.S. Coast Guard suspended the search for the 12 missing Marines off Haleiwa at sunset.
“The decision to suspend the search without finding survivors is particularly difficult,” said U.S. Coast Guard Capt. James Jenkins.
A search, led by the Marine Corps, will continue for debris and remains, but the focus of the search is changing to a recovery and salvage operation.
An inquiry board will investigate the crash and come up with recommendations and findings.
Some aircraft debris has been recovered from the ocean floor about 2 miles from shore in 350 feet of water, Jenkins said.
A high surf warning is posted for Wednesday as wave faces are expected to rise to 30 to 40 feet on the North Shore, a factor which would have complicated the search had it continued Wednesday.
The Coast Guard and other agencies searched for five days since two Kaneohe-base Marine Super Stallion helicopters crashed last week in the ocean about 2 miles from shore.
All four life rafts were recovered, but they were empty and there is no indication anyone had been on any of the rafts, based on their condition and lack of any personal effects, said Coast Guard Petty Officer Tara Mole.
A good Samaritan spotted the final raft on Monday afternoon, and a Coast Guard vessel recovered it 3 miles north of Oahu.
The search has covered 24,150 square miles of ocean and shoreline between Haleiwa and Kahuku.
The CH-53E helicopters carrying six crew members each failed to return to Marine Corps Base Hawaii following a nighttime training mission Thursday. Hours later, authorities spotted debris 2 1/2 miles off the coast.
Some of the life rafts were inflated, but it was unclear how they got that way. There are various ways that could happen, including a cord being pulled by debris, said Marine Capt. Timothy Irish.
The Associated Press contributed to this story.