She won her first World Championship medals in Oslo 2011, a silver in the team sprint and a bronze in 4 × 5 km relay.

The 2017 World Championships on home soil in Lahti, Finland, saw Pärmäkoski win her first and to date only individual WCH medal, a silver in the 15 km skiathlon behind Marit Bjørgen.

Her good form from the Olympics continued for the rest of the season; among other podiums, she won the 10 km classical competitions in Lahti and Falun.

She won her next medal at the next Olympics in Beijing in 2022, where she seized a bronze in 10 km classical after Therese Johaug and Finnish teammate Kerttu Niskanen, with only 0.1 seconds separating her from Natalia Nepryaeva of the ROC who came in fourth.

As the anchor for Finland in both the team sprint and relay, Pärmäkoski finished 4th, with bare seconds from medal placements.