Situma, who left Homeboyz early in June, penned a two-year deal with the former Kenyan Premier League champions on Wednesday.
The former Tusker defender becomes the third signing for Mathare in the mid-season transfer window. "James Situma is our third signing of the mid-season transfer window after agreeing to a two year deal," the club confirmed in a statement obtained by Goal.
Situma has two KPL medals in his cabinet, with both Tusker and Sofapaka as well as an international stint with Albanian side FK Tirana.
Situma joined former teammate David Okello, who replaced Robert Mboya in the goalkeeping department after penning a deal with Francis Kimanzi side.
Emmanuel Otieno is the other signing for Mathare United this mid-term transfer window. Mboya terminated his contract to join Wycliffe Kasaya, who also left for greener pasture at Sofapaka.