The 100 fishermen in custody have been taken to Trincomallee, Inspector of 'Q' branch of Tamil Nadu police Kennedy and Rameswaram fishermen's association president Emirit said.
The fishermen, hailing from Karaikal, Nagapattinam and Jagathapattinam, had been arrested for allegedly fishing in Lankan territorial waters, officials said.
While Nagapattinam and Jagathapattinam are in Tamil Nadu, Karaikal is part of the Union Territory of Puducherry.
Earlier, as many as 227 fishermen from Nagapattinam district in Tamil Nadu were today detained by Lankan Navy personnel when they were fishing in the Palk Strait but later released, fisheries officials said.
Officials said the fishermen would reach India either tonight or tomorrow.
Pushparaj said they could have been arrested for not having a proper fishing token issued by the department and for crossing the International Maritime Boundary line.