Rocastle was eligible to play for both Grenada or Jamaica as his father was from Grenada and his mother was from Jamaica. He made his Grenada international debut on 26 November 2010, in a 2010 Caribbean Cup match against Martinique at the Stade d'Honneur de Dillon in Fort-de-France. He was named by coach Mike Adams in the 2011 CONCACAF Gold Cup at the United States, and played the first half of the 4–0 defeat to Jamaica at The Home Depot Center, before being taken off for Lancaster Joseph. Grenada exited the competition after finishing bottom of their group. On 15 November 2012, Rocastle scored from an indirect free-kick from 22 yards out in a 1–1 draw with French Guiana.