The Kolkata-Dhaka-Agartala service will reduce the travel time between the capitals of India's West Bengal and Tripura states by one-third.
The Kolkata-Agartala bus service via Dhaka reached Agartala last midnight amid warm welcome from people of Tripura.
Senior state officials received the bus at the Indo-Bangla border of Tripura.
People waved at the bus as it passed through different areas and halted at the state capital terminus.
"This has been made possible by Prime Minister Narendra Modi, West Bengal Chief Minister Mamata Banerjee and Bangladesh Prime Minister Sheikh Hasina," one of those present at the site, said.
Marking Mr Modi's maiden visit to Bangladesh, two bus services connecting key cities in the two countries were flagged off yesterday in Dhaka by the three dignitaries to boost connectivity and enhance people-to-people contact.
"I wish you all a very happy journey," Mr Modi had said after jointly flagging off the Kolkata-Dhaka-Agartala and Dhaka-Shillong-Guwahati bus services with his Bangladeshi counterpart and West Bengal Chief Minister.
During the flag off ceremony on the first day of his visit yesterday, Mr Modi handed over a symbolic ticket of the Agartala-Dhaka-Kolkata service to Ms Hasina and in return, she handed over a symbolic ticket of Dhaka-Shillong-Guwahati service to him.
Ms Banerjee gave Ms Hasina a symbolic ticket of the Kolkata-Dhaka-Agartala service.