In 1999, Addadi attended the All-Africa Games in Johannesburg, South Africa. He broke the host nation's stranglehold after winning the 100 m backstroke title in 58.28, edging out Seychelles' Benjamin Lo-Pinto by almost a full body length. He also added a bronze to his hardware in the 100 m butterfly at 56.30, finishing just outside a top two finish from the South Africans.