The 22-year-old joins the club from American college, Southeastern Fire, and has been handed the jersey No.19.
Kanu becomes the first Nigeria international at the Nervion club.
The Falcons star told the club’s official website that she was delighted joining the club.
“I’m very happy to join this great club like Sevilla FC, which has a great history,” Kanu told Sevilla’s official website.
“I can’t wait to make my debut.”
She also tweeted, “Thank God for his unconditional grace upon me. I am super honoured for this great opportunity to represent Sevilla FC.
“A big thank you to those who helped and supported me in making this deal a success. I can’t wait to get to work.”