The Sweden international, who has also played for Bolton Wanderers and Deportivo La Coruna, joins the Pro League side on an 18-month deal, while rivals Al Nasr have signed Japan's Takayuki Morimoto on loan.
Baniyas sign former Roma midfielder Christian Wilhelmsson
Baniyas have completed the signing of Christian Wilhelmsson, the much-travelled Swedish midfielder, on a one-and-a-half-year deal.
The 33-year-old, who has played in the top divisions of Italy, France, Spain and England, was recently released by Los Angeles Galaxy, having helped the American side secure the MLS championship during a brief spell there.
Wilhelmsson does have experience of football in the Gulf region, though, as he spent three years in Saudi Arabia with Al Hilal, and was later loaned to Al Ahli, then of the Qatar Stars League.
"I know Baniyas and their good local players thoroughly well," said Wilhelmsson, who also owns a home in Dubai.
"I will try to make the required addition to serve the team and my objective is to bring happiness to the team's supporters and gain their full confidence."
Wilhelmsson cites Nantes, AS Roma, Bolton Wanderers and Deportivo La Coruna as past employers, and has formed an integral part of the Swedish national team since making his international debut in 2001.
The Malmo-born star has 79 caps in total, including those earned at the 2006 World Cup. He has also featured for his country in the past three European Championships.
It remains unclear as to who Wilhelmsson replaces at Baniyas, currently fourth in the Pro League, as the Abu Dhabi club already boast Mohamed Zidan, Nick Carle, Andre Senghor and Ismail Belmaalem as their four foreign players.
Elsewhere, Al Nasr have recruited Takayuki Morimoto, the Japan striker, to fill the Asian spot vacated by Nashat Akram.
Morimoto arrives at Al Maktoum Stadium from Catania, the Italian Serie A club, on loan for the rest of the season.
The 24 year old, who at 15 became the youngest player to debut in the J League, has made more than 100 appearances since moving to Italy in 2006.