In spite of a strong previous year, he managed only sixth at the Good Luck Beijing test event marathon (with a time of 2:23:50 hours) and was the last runner to finish in the 2008 Olympic marathon, which took him 2:41:08 hours to complete the course. In 2009 he was runner-up at the Japanese Corporate Team Half Marathon Championships with a time of 1:01:29 hours (the second best of his career) and was eighth at the 2009 London Marathon with a run of 2:09:16 hours. He was the best non-African performer in the marathon at the 2009 World Championships in Athletics, taking sixth place in the rankings. He ran at the 2009 IAAF World Half Marathon Championships, but managed only 32nd place overall. Sato was the fastest on his 10K leg of the International Chiba Ekiden and helped Japan win the title in the ekiden relay event.