In early 1986 the Christmas Island Assembly held a design competition for an island flag ; the winning design was adopted as the informal flag of the territory for more than ten years , and in 2002 it was made the official flag of Christmas Island . In early 1986 , the Christmas Island Assembly held a design competition for an island flag ; the winning design was adopted as the informal flag of the territory for over a decade , and in 2002 it was made the official flag of Christmas Island .