A sandwich chain is offering discounts to customers who opt not to use paper cups.
Pret A Manger bosses say they will cut 25p off the price of hot drinks to people who bring in reusable cups.
Earlier this year researchers suggested charging for disposable coffee cups.
Academics at Cardiff University estimated that 2.5 billion disposable coffee cups were used in the UK every year - and about 25,000 tonnes of waste created.
They said a study showed that charging might cut the use of disposable cups by up to 300 million a year.