The 24-year-old striker joins Simba after his contract with Ghana's Asante Kotoko club ended last month.
He will be a valuable asset for Simba as they seek success in the Tanzanian and African competitions.
Mukwala played well during his time at Kotoko, scoring over 25 goals in 65 league appearances.
He impressed immediately in his first season, scoring 11 goals, followed by 14 goals in the recently concluded season, including a memorable goal against rivals Hearts of Oak.
Mukwala has played for Vipers FC, Maroons FC, all of Uganda before joining Ghana's Asante Kotoko.
