Larsson represented Sweden at the 2010 World Junior Championships, held in Saskatoon and Regina, Saskatchewan. At the 2010 World U18 Championships, he was selected as the best defenceman of the tournament. When Larsson played for Sweden at the 2011 World Junior Championships, he repeated his scoring of one goal and three assists from the previous tournament, which earned him the distinction of being Sweden's highest-scoring defenceman at the tournament.