The hostages were crew members of the Malaysian-flagged MV Albeldo hijacked 38 months ago near Somalia’s territorial waters.
The pirates opted to release them after no one had come forward to negotiate their release, SomaliCurrent.com reported, quoting local media.
The pirates demanded ransom for their release in the early days of their captivity, but the Thai government refused to talk to them, the report said.
Last year, the families of the hostages sent an open letter to the pirates, requesting the unconditional release of the Thai hostages.
A spokesman for the pirates said that they could not afford to hold the captives and were now ready to free them as soon as possible.