His debut in B-Nordic Combined World Cup gave Shun Yamamoto on 19 January 2007 in a mass start in the Italian Val di Fiemme , in which he finished in 57th place. At the Nordic Junior World Ski Championships in 2007 in Tarvisio , he was 34th in the Gundersen competition on the normal hill with a subsequent cross-country distance of ten kilometers. After a break of several years, he returned in January 2010 to the B-World Cup, renamed the Continental Cup in 2008. His best result in this competition series was a win on January 11, 2013 in Tchaikovsky , Russia, ahead of the Austrian Marco Pichlmayer and the French Nicolas Martin . At the same time, this is his only podium finish in the Continental Cup to date. In the 2012/13 season , the best overall result was achieved with 15th place.
He started in the Nordic Combined World Cup for the first time on January 23, 2010 in Schonach . The first place in the points came a little more than three years later, on January 26, 2013, in Klingenthal . The 2012/13 season he finished with 31 points in 48th place in the overall World Cup.