Internationally, Loob first skated for the Swedish junior team at the European Junior Hockey Championship in 1978. He then won bronze medals with the Swedish team at both the 1979 and 1980 World Junior Championships. He finished third in tournament scoring in 1980 with nine points (seven goals, two assists) and was named an all-star. He debuted with the senior team in 1982, scoring three goals in eight games for the Swedish team that finished fourth in the World Championship, but won a silver medal in the European Championship, which counted results amongst only participating European nations.