The trams were designed by former Ukrainian ČKD branch Tatra-Yug at Pivdenmash aerospace factory in Dnipro.

The development of the Tatra T6B5 modernization for Kyiv (hence the letter 'K' in the name)[1] started in the late 90's, the first prototype was built in 2001 and sent to the capital for testing.

[4] In 2007 K1 got new doors and seats, while the original K1 prototype has been modernized to match the serial models and was sent to Konotop.

K1T2 was planned as a longer version of K1M8, however Tatra-Yug never built a single unit of it so it remains an unrealized project.

The development of the new modification of K1 began in 2015, Tatra-Yug hosted a competition for the best exterior design and chose the winner in 2016.

[9] In 2018 Tatra-Yug took an order of Egyptian city of Alexandria to develop a narrow gauge version of K1.