Mehdi Addadi (Arabic: مهدي عدادي; born February 13, 1978) is an Algerian former swimmer, who specialized in sprint backstroke and butterfly events.

Ten years later, in 1997, Addadi left his homeland Algeria to move to the United States, where he received a full scholarship to attend Bolles School in Jacksonville, Florida.

[2] During his short stay, Addadi trained under Gregg Troy, a coach who produced numerous top-class swimmers including Ryan Lochte.

[5] In his senior season, Addadi was named the Most Outstanding Swimmer of the Year at the Eastern College Athletic Conference Championships after breaking a school record in the 100-yard butterfly.

[9][10] Five days later, in the 100 m butterfly, Addadi challenged seven other swimmers in the same heat, including Guam's 28-year-old Daniel O'Keeffe and Bosnia's three-time Olympian Janko Gojković.