Kodama, who starts for Nihon University, ran her first race in the Far East Cup in Otoineppu in December 2012 . She finished 39th over 5 km freestyle and 37th place over 5 km classic. At the Junior World Championships in 2016 in Râșnov , she came 64th in sprint, 47th place over 10 km freestyle and 41st place over 5 km classic. At the beginning of the 2017/18 season she started in Davos for the first time in the World Cup and achieved 80th place in the 10 km freestyle. In the further course of the season she won the overall ranking of the Far East Cup with seven top ten placings, including three third places, and finished 61st at the World Cup final in Falun . At the U23 World Championships in Goms in 2018 , she came 47th in sprint, 42nd place over 10 km classic and 32nd place in skiathlon . After finishing 56th in the Lillehammer Triple at the beginning of the 2018/19 season, she won the Far East Cup in Otoineppu over 5 km freestyle and in Sapporo over 10 km freestyle. In addition, she reached the second and third place each time and thus reached second place in the overall ranking of the Far East Cup. At the U23 World Championships in Lahti in 2019 , she finished 60th in the sprint, 28th in the 15km mass start race and 20th in the 10km freestyle. At the highlight of the season, the Nordic World Ski Championships 2019 in Seefeld in Tirol , she finished 42nd in the 30 km mass start race and 14th place in the relay. At the Winter Universiade in Krasnoyarsk in March 2019 , she finished fifth in the 15 km mass start race and won the silver medal with the relay.