Co-developed by San Francisco-based self-driving car operator Cruise, the project will offer "an entirely new kind of mobility experience" in Japan, Honda said in a statement.
"This will be a major step toward the realization of an advanced mobility society," its chief executive Toshihiro Mibe said.
The project is also aimed at "helping address societal issues facing Japan, such as the taxi and bus driver shortage," Honda added.
Autonomous vehicles are being pushed by Japan's government as the country battles a rapidly ageing population and persistent labor shortages.
In 2020, Japan became the first country in the world to allow a vehicle capable of taking full control in certain situations to operate on public roads.
Auto giants from Toyota to Nissan are also trialling self-driving buses and taxis.
Honda's newly announced service will feature a "vast cabin space" capable of accommodating six passengers, stripped of a driver's seat and a steering wheel.
It will "pick up customers at a specified location and drive them to the destination, entirely through self-driving," with customers able to complete the whole process on a smartphone app, according to Honda.
"Dozens" of the driverless cars are expected to be launched in Tokyo in early 2026, with the developers then hoping to expand the project to a fleet of 500, and to areas outside central Tokyo.
"The benefits of AVs (autonomous vehicles) -- from safety to accessibility -- are too profound to ignore," Mary Barra, chair and CEO of GM, said.
But self-driving cars are no stranger to controversy, with safety under scrutiny as operators including Cruise increasingly gain traction in California.
Honda, GM and Cruise aim to establish a joint venture dedicated to their new initiative in 2024, pending regulatory approvals.