Fida Hussain Janwari, a senior police official in the port city of Karachi said Pakistan’s Maritime Security Agency also captured 10 boats belonging to the fishermen.
“These 66 fishermen were handed over to police today (on Monday). We have begun legal proceedings and they will be soon presented in a court,” he told AFP.
The two countries frequently carry out such arrests as the maritime border in the Arabian Sea is poorly defined and many fishing boats lack the technology needed to be certain of their precise location.
The fishermen often languish in jail even after serving their term, as poor diplomatic ties between the two arch-rivals mean fulfilling official requirements can take a long time.
Hassan Setho, a senior prison official, said more than 400 Indian fishermen were currently detained in the southern city of Karachi.
India and Pakistan have fought three wars since gaining independence from Britain in 1947.
Earlier this month, India’s Foreign Minister Sushma Swaraj held talks with her Pakistani counterpart Sartaj Aziz in Islamabad on the sidelines of a regional summit on Afghanistan, where they jointly announced they would resume high-level peace talks.