Estonian firm Ridango's contactless payment ticket system is now operating on public transport in the Ukrainian capital.
The machines are currently used on public transport in Tallinn, Tartu and Pärnu and are now in use on buses, trams and trolleybuses in Kyiv.
Contactless payments can be made from bank cards, phones or smart watches.
Project manager Vahur Viigimäe said it will simplify journeys for passengers already facing difficult conditions.
"It is very important that residents can continue their daily tasks as efficiently as possible even in the middle of a war," Viigimäe said.
The city's public transport was halted between February 24, the day Russia launched its full-scale invasion, and May 9. The number of people currently using transport in Kyiv is below pre-war levels, Ridango said in a statement.
"One million trips are validated every day, between 29 and 30 million per month," Viigimäe said. "It is perhaps half what it was before the war, but it is clear that convenient public transport is extremely necessary for the people of Kyiv."
Editor: Helen Wright