Which Greek island was the main filming location of the 2008 film Mamma Mia!?

Most of the outdoor scenes were filmed on location at the small Greek island of Skopelos, and the seaside hamlet of Damouchari in the Pelion area of Greece. Kastani beach on the south west coast was the film's main location site. The producers built a beach bar and jetty along the beach, but removed both set pieces after production wrapped.