Oinas, who starts for Taivalkosken Kuohu , made her international debut on August 12, 2016 in Vuokatti at home as part of the Youth Cup , where she finished sixth on the middle hill and over four kilometers at the Gundersen competition on the following day . In April 2017 Oinas won the Finnish championship title in Taivalkoski for the first time , which she was able to repeat in March 2018.
At the beginning of the 2018/19 season , Oinas made her debut in the Continental Cup, which is the highest competition series for women. She took part in the competitions on the two weekends in Steamboat Springs and Park City and came in eighth three times. At the end of January 2019, Oinas took part in the Nordic Junior World Ski Championships 2019 in Lahti , where a junior women competition was held in the combination for the first time. In the Gundersen competition, she took fifth place. In addition, she competed in ski jumping competitions and achieved 52nd place in individual and thirteenth place in mixed team jumping together with Julia Tervahartiala , Mico Ahonen and Jonne Veteläinen . At the 2020 Winter Youth Olympic Games in Lausanne , Oinas finished 18th in the Nordic Combined.