On their website, Pret names these items as vegan:

Sweet Potato and Cauliflower Curry soup, Moroccan Lentil soup,
Falafel Mezze Salad, Pret’s Grains & Greens Salad, Hummus & Crunchy
Veggie Flatbread wrap, dairy free yogurt with nuts and berries, fruit,
Overnight Oats with nuts and dates, Dark Chocolate with Sea Salt,
and Oatmeal for breakfast.
See: https://www.pret.com/en-us

For information about eating at other restaurant chains, see
http://www.vrg.org/fastfoodinfo.php

To find vegetarian and vegan restaurants, go to
http://www.vrg.org/restaurant/index.php

The contents of this posting, our website and our other publications,
including Vegetarian Journal, are not intended to provide personal
medical advice. Medical advice should be obtained from a qualified
health professional. We often depend on product and ingredient
information from company statements. It is impossible to be 100% sure
about a statement, info can change, people have different views, and
mistakes can be made. Please use your best judgement about whether a
product is suitable for you. To be sure, do further research or
confirmation on your own.