Yes, if tickets are still available, you can purchase them at the venue. Each Festival venue has an on-site Box Office that opens 1 hour and 30 minutes before performance time and operates only on performance days.
In addition, the Spoleto Festival Ticket Kiosk will be open daily beginning May 18, from 10:00am to 4:00pm, offering full ticketing services. The kiosk location will be announced closer to the Festival.