The Flemish transport company De Lijn announced on Friday that it is now possible to pay for travel using eco-cheques or vouchers.
Currently, this option is only available at ticket machines, and it is not yet possible to use eco-vouchers onboard vehicles or online.
Passengers can use eco-vouchers to purchase single tickets or multi-trip passes of 10 or 50 journeys.
"We are delighted to be able to accept eco-vouchers and hope this will make it easier and more environmentally friendly for our customers to travel," said CEO Ann Schoubs.
Presently, 2.3 million workers receive up to 250 euros in eco-vouchers annually, according to figures from the umbrella organisation VIA.
However, the system could be abolished in the future, according to a leaked note from federal formator Bart De Wever, who has proposed eliminating eco-vouchers in exchange for increasing the value of meal vouchers.