when does mail run on saturday depends on the location and type of mail service being used. Typically, USPS delivers mail on Saturdays, and the delivery time is similar to weekdays. However, some services, like First-Class Mail and Priority Mail, may arrive earlier, while others like bulk mail or certain business mail may take longer. It’s important to note that some mail services, like Priority Mail Express, may include Sunday delivery as well, but not all locations have this service available.