Sometimes all you have to do is ask for "HELP": That's what three men stranded on a deserted Pacific island learned earlier this week, writing the message in palm fronds which were spotted by US rescuers.

The trio, all experienced mariners in their 40s, became stranded on a lonely island after setting off from Micronesia's Polowat Atoll on March 31 in their motor-powered skiff which subsequently experienced damage.

They were reported missing last Saturday by a woman who told the US Coast Guard her three uncles never returned from Pikelot Atoll, a tiny island in the remote Western Pacific.

"In a remarkable testament to their will to be found, the mariners spelled out 'HELP' on the beach using palm leaves, a crucial factor in their discovery," said search and rescue mission coordinator Lieutenant Chelsea Garcia.

She reported that the trio was discovered Sunday on Pikelot Atoll by a US Navy aircraft.

"This act of ingenuity was pivotal in guiding rescue efforts directly to their location," she said.

The aircraft crew dropped survival packages, and rescuers one day later dropped a radio which the mariners used to communicate that they were in good health, had access to food and water, and that the motor on their 20-foot (six-meter) skiff was no longer working.

On Tuesday morning a ship rescued the trio and their equipment, returning them to Polowat Atoll, the Coast Guard said.

In August 2020, three Micronesian sailors also stranded on Pikelot were rescued after Australian and US warplanes spotted a giant "SOS" they had scrawled on the beach.