Loob appeared in his first best-on-best world tournament at the 1984 Canada Cup, where his ten points in eight games was second in team scoring, one behind Kent Nilsson. He scored two goals and two assists in the two game final series, which Sweden lost to Canada. A shoulder injury prevented Loob from playing in the 1987 Canada Cup, but he did appear at the 1987 World Championship. He scored nine points in eight games to help Sweden win its first World Championship in 25 years. He made two additional world championship appearances, winning a silver medal at the 1990 tournament and a second gold in 1991. In the concurrently held European championships, Loob and the Swedes won gold in 1990 and silver in 1991.