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 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.