In 2019, in her last junior year, she first won two gold medals at the Dutch U20 championships (400 m hurdles and 400 m indoor), and added her first senior title at the national indoor competition (400 m). In June, Bol won the 400 m hurdles race at the meet in Geneva, qualifying for the Doha World Championships. In July, she confirmed herself as the continent's best under-20 runner in her, since that year, signature event of the 400 m hurdles, with a gold medal at the European U20 Championships. At the World Championships, Bol reached the semi-finals with new personal best and national U20 record of 55.32 s in the heats, becoming the 2nd fastest under-20 European woman in history. Dutch 4x400 m relay placed seventh.