[1] Thelma competed at the 2017 Northern European Championships in Tórshavn where she helped Iceland place second as a team.

[4] In October Thelma made her World Championships debut; she helped Iceland finish 36th during qualifications.

[1] She later competed at the Nordic Championships, winning gold on balance beam and helping Iceland place third as a team.

In September Thelma competed at the Szombathely Challenge Cup where she qualified to the vault event final; she finished seventh.

[10] Thelma ended the year competing at the Northern European Championships where she won gold on the uneven bars.