Malaysian police officials said the three Indonesians and a Filipino returned by boat to Sabah on Borneo island around dawn yesterday.
They were identified as Indonesians Amir Nangi, 50, and Arsyad Sagoni, 45, Suwito, 23, and Filipino Azarah Sariban, 50.
They were taken to a hospital for medical tests, Malaysias Bernama state-run news agency reported.
At a press conference in Kota Kinabalu, Sabah Police Commissioner Ilyas Ibrahim confirmed that the hostages have been released but refused to give details on how they were freed.
Hospital officials could not immediately be reached for comment.
Two of the men were ill and unable to walk, Bernama said.
Malaysian police said the hostages arrived by boat near Sandakan Yacht Club at about 6 a.m. (Sabah time) after a rough seven-hour sea journey.
The workers were among three Indonesians and three Filipinos seized last November from the remote Borneo Paradise Eco-Farm Resort in Sabah.
They were taken by speedboat to Tawi-Tawi waters, sparking a land, sea and air search by Malaysian and Filipino police and troops.
Last December, soldiers found Filipino Noel Arcousel after he escaped from the island town of Panglima Sugala in Tawi-Tawi.
He told authorities the kidnappers belonged to the Abu Sayyaf, which launched similar boat raids on a resort off Sabah in 2000, kidnapping tourists and demanding ransom.
The Philippine Army said Alcousels story was inconsistent and that they doubted its veracity.
Malaysian officials identified the kidnappers as pirates who reportedly sought a multimillion-dollar ransom for the workers.
However, Malaysia said it refused to bow to any such demand.
Reports said the release of the others was negotiated by a Malaysian businessman who previously helped secure the freedom of local hostages taken by the Abu Sayyaf.
It was not immediately clear whether any ransom had been paid.
The Philippine military and police have yet to locate three foreign hostages an Indonesian and two Malaysians who were the skipper and crew of a tugboat seized by Abu Sayyaf gunmen early this year in Lingkian island near the Malaysian border.
The victims were reportedly brought in one of the islands of Tawi-Tawi, but troops and police failed to locate any of the hostages nor their captors. Roel Pareño, AFP