The Pakistan Maritime Security Agency arrested the Indian fishermen late on Thursday night.
"The Indian fishermen strayed into our area and were warned several times to go back but then arrested when they didn't heed the calls," spokesman Commander Naeem said.
The fishermen were interrogated and then handed over to Docks Police in Karachi, the spokesman for the MSA said.
This was the fourth incident of Indian fishermen being arrested in Pakistani waters during the month of September, he said.
A total of 94 fishermen were arrested and 21 boats seized by the MSA, he said. India and Pakistan arrest hundreds of fishermen on charges of violating the maritime boundary.
Dozens of fishermen have spent years in jail even after completing their prison terms.
The governments have in the last few years exchanged or released the fishermen as part of the slow moving peace process.
In recent months, both countries have taken steps to speed up the release of the fishermen.
