He broke the 2:10 barrier at the 2011 Lake Biwa Marathon, having his best finish yet with a run of 2:09:31 for fourth. As one of the leading Japanese men that season, he was selected for the 2011 World Championships in Athletics in Daegu. In his first international appearance for Japan he performed well and took tenth place in the World Championship Marathon. He was Asia's second fastest performer, after his team mate Hiroyuki Horibata, with whom he secured the team silver medals in the 2011 World Marathon Cup. That year he also ran track bests of 14:04.31 minutes for the 5000 metres and 29:04.24 minutes for the 10,000 metres. A return to the Lake Biwa race in 2012 saw him finish in the same position, but in a personal best of 2:08:53 hours (the second Japanese behind Ryo Yamamoto). This performance earned Nakamoto another international selection and competing for Japan at the 2012 London Olympics he ranked as Asia's best performer in the Men's Olympic marathon, taking sixth place with a run of 2:11:16 hours.