In February, Eythora competed at the Reykjavik International Games, winning all-around and balance beam gold, vault and floor exercise silver, and uneven bars bronze. In April, she competed at the 2017 European Artistic Gymnastics Championships. In qualifications, she qualified for the individual all-around final, the balance beam final and the floor exercise final. In the individual all-around, she started well with vault, but a fall on the uneven bars and balance beam caused her to be lower in the rankings. She finished with a good floor exercise routine, and ended in 12th place. In the balance beam final, Eythora competed a clean routine and finished second behind Cătălina Ponor. In the floor exercise final, she finished in third place behind Angelina Melnikova and Ellie Downie. Thorsdottir competed at the 2017 World Championships but did not qualify for any individual apparatus finals.