Donsu left Ghana on Saturday afternoon in the company of the club’s Chief Executive James Essilfie to put pen to paper.
It is believed that the Mecca-based side made an offer not less than US$ 250,000 which was accepted by the Tarkwa-based side.
Al Wahda have a partnership agreement with Medeama making his transfer to the Gulf country easier.
Donsu, an offensive midfielder, was second joint top scorer in the Ghana Premier League with 15 goals.
He had been linked with moves to major European sides including English Premier League side Middlesbrough.