Six Indian fishermen and two trawlers will be handed over to authorities off the coast of Kankesanturai in the north, naval spokesman Commander Kosala Warnakulasuriya said.
Twelve Sri Lankan fishermen and their two trawlers would be released by India, he said.
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An Indian Coast Guard vessel will bring the Sri Lankan fishermen, Warnakulasuriya said.
It could not immediately be ascertained when the exchange would be made.
The Tamil Nadu government has been mounting pressure on the centre to take strong action against Sri Lanka for detaining fishermen.
Sri Lanka claims that the Indians repeatedly cross the International Maritime Boundary and indulge in "poaching" in its territorial waters despite warnings from the navy.
The Lankan Navy arrested a total of 40 fishermen in the last two days while they were fishing in the Palk Strait.
The families of Sri Lankan fishermen held in India accuse the government here of failing to take swift action to secure their release.