[4] Östlund made her ISU Junior Grand Prix (JGP) debut in the 2014–2015 season, placing 17th in Courchevel and 14th in Ostrava.

Making her senior international debut, she placed 7th at the Warsaw Cup, a Challenger Series event in November 2016.

At the Nordics Open, held in March in Reykjavík, Iceland, she outscored both of her national co-medalists for the bronze medal and joined former world champions Carolina Kostner and Elizaveta Tuktamysheva on the podium.

In September, Sweden qualified a spot at the 2018 Winter Olympics due to Matilda Algotsson's result at the 2017 CS Nebelhorn Trophy.

In January, she finished as Sweden's top ladies' entry at the 2018 European Championships, having placed 6th in the short program, 20th in the free skate, and 17th overall.