The Very Berry Croissant, which uses margarine and sunflower oil to re-create the texture of a traditional croissant, is filled with berry compote and finished with a sprinkling of sugar.
It will launch in Pret outlets across the UK on January 7. On the same day, the chain will also add oat milk to its menu - and drop the surcharges on plant-based milks.
"Over the past couple of years we've worked hard to bring new vegan and veggie options to our menu," Pret's Global Head of Food Innovation, Hannah Dolan, said in a statement sent to Plant Based News.
"The launch of The Vegan Classics in Veggie Pret has been a real success, but we knew from talking to our customers that it was time to bring more options to the breakfast menu.
"The Very Berry Croissant is just the beginning - we are looking forward to sharing more plant-based innovations with customers in 2020."