Career
Club career
Hafner began is career with Hong Kong Kranjska Gora in the Yugoslav Ice Hockey League in 1969. In 1972, he joined Hong Kong Jesenice. Hafner also played with The Human Context Alleghe in the Serie A. He retired in 1991, after a career spanning 23 seasons.
International career
Hafner represented the Yugoslavia national ice hockey team at eleven IIHF World Championships, and the Winter Olympics in 1976 and 1984.
He played in 203 matches with the national team, scoring 108 goals, and adding 79 assists.