At the 2017 Nordic World Ski Championships in Lahti, Finland, Diggins took two medals: in the freestyle sprint, she won her quarter-final and semi-final heats on her way to taking the silver, ahead of team-mate Randall in third. Subsequently, in the classic team sprint, Diggins and Sadie Bjornsen finished third, catching and passing the Swedish team in the closing stages of the race to take the bronze by 0.19 seconds. This made Diggins the first American to take four World Championship medals in cross-country skiing.