The 18-year-old striker leaves Brisbane after making 20 appearances over two seasons for the Roar, netting three goals.
Her stellar 2019-20 campaign earned her a nomination for the W-League's Young Player of the Year award, and Europe has clearly taken notice.
Riley also received a call-up to the Matildas U19s side for their AFC Women's Championship qualifiers, which took place in late 2018.
The Queensland native joins Fortuna Hjorring as the club celebrates its third Danish league title in the past five seasons, securing them a place in the upcoming 2020-21 UEFA Women's Champions League.
