The $1bn (£630m) Russian-built vessel is being leased by the Indian navy for the next 10 years. It was handed over to India in eastern Russia in January.
India previously operated a Soviet nuclear submarine until 1991.
It now rejoins China, Russia, the US, the UK and France as an operator of nuclear submarines.
India is also developing its own nuclear-powered submarine which is expected to be ready by the end of this year.
The 8,140-tonne Akula II-class submarine, built by the Russians as the K-152 Nerpa, has been renamed by India as the INS Chakra II.
Significantly, the submarine will be deployed on India’s east, and not west, coast which means China -not Pakistan – is the clear threat.
One naval officer told me that they are aware of the increased Chinese naval activity off Indian waters.
This then is India’s first, small step to counter that.
India and Russia are long-time allies and Russia supplies 70% of India’s military hardware