One passenger was found dead, while many other rescued from the boat were dehydrated, Naval spokesman Kosala Warnakulasuriya said.
Among those rescued were three women and three children.
The fishing craft was spotted off the eastern waters and it was not immediately clear where the vessel was headed or whether they were asylum seekers, he said.
"We sent three ships for the rescue at a location 50 miles off the eastern coast of Akkaraipattu," Warnakulasuriya said.
"Some have been admitted to a local hospital. Others are being taken to Colombo."
"We have not been able to get much information about their port of origin or the destination, but we have asked the embassies of the two countries to help us with translations," the Naval spokesman said.
Sri Lanka in the recent years stepped up its Naval patrol to deter illegal immigration rackets to Australia on fishing boats.
Under pressure from Australia the Sri Lankan Navy have arrested more than 1,200 would be illegal immigrants throughout last year.
