He burst onto the international scene with his performances in the 2003 Rugby World Cup, particularly against France and Scotland. Early in the second half against France, Caucaunibuca received a long cut-out pass just outside his own 22, and proceeded to run pass his opposite number Aurélien Rougerie as well as two covering defenders on his way to scoring under the posts. In Fiji's final Pool B match against Scotland, a match that would decide who would finish behind France in their pool, Caucaunibuca stole the show in the opening exchanges with two remarkable solo tries: one finishing from about 25 yards out down the left-hand touchline with a one-handed diving finish, the second once again starting from just outside his 22 and running the length of the field, easily evading tacklers to score.