She started her career with Keflavík in the Icelandic Úrvalsdeild kvenna where she won the national championship in 2017.
After coming up through Keflavík junior teams, Þóranna played her first games in the top-tier Úrvalsdeild kvenna during the 2015–2016 season.
She helped Keflavík to the national championship in 2017 when they beat three-time defending champions Snæfell in the Úrvalsdeild finals.
[1] She bounced back the following season and averaged 9.4 points and 5.4 rebounds for Keflavík before the rest of the season and playoffs where canceled in March 2020 due to the coronavirus pandemic in Iceland.
[3] Þóranna started playing with Iceland's junior national teams in 2014.