“I’ve always had the thought to playing abroad at some point in my career and I just had the feeling that this year was the right time to do that.”
City finished fourth in the WSL last season, outside the Champions League places and 17 points behind winners Chelsea.
Lohmann said: “I definitely want to win a title because I can see that’s possible.
“I think things have probably been quite tough in the last few months or year and everyone is really hungry to do better.”
Lohmann is City’s third signing of the summer, following the arrivals of Iman Beney and Jade Rose.
