The Saudi outfit confirmed the signing on Friday, welcoming the Ghana international in a social media announcement that described him as a "legend" and suggested that his arrival was a natural fit for the club.
Partey joins Al Shabab as a free agent after spending the previous season with Villarreal in Spain. The midfielder moved to the Yellow Submarine following a five-year spell at Arsenal, where he established himself as an important figure in the Premier League.
During his time with the Gunners, Partey made 167 appearances across competitions and scored nine goals. His departure from Arsenal brought an end to a significant period in England before he opted for a return to Spain with Villarreal.
The 33-year-old's career has also included a lengthy spell at Atletico Madrid. Having progressed through the Spanish club's youth system, Partey went on to make 188 senior appearances under Diego Simeone and helped Atletico win the Europa League in 2018.
He also received a LaLiga winners' medal for Atletico's title-winning campaign despite joining Arsenal early in the 2020/21 season, having made enough appearances for the Madrid club during the early stages of that campaign.
At international level, Partey has earned 60 caps for Ghana and scored 15 goals. His involvement at the 2026 FIFA World Cup was overshadowed by legal proceedings in the United Kingdom after he was initially denied entry into Canada.
Partey has been charged with seven counts of rape and one count of sexual assault relating to allegations between 2020 and 2022. He has pleaded not guilty to all charges, while his trial is scheduled to begin at Southwark Crown Court on June 8, 2027.
Despite the circumstances, Partey featured in Ghana's other three World Cup matches, including a goalless draw against England and a 1-0 defeat to Colombia that ended the Black Stars' campaign in the round of 32.
At Al Shabab, Partey will link up with former Premier League players Josh Brownhill and Daniel Podence, as well as his former Atletico Madrid teammate Yannick Carrasco.