The former captain, who now plays in Qatar, met the current team and management for over an hour at their hotel before speaking to supporters and posing for photographs
The 35-year-old, who plays for Qatari side Al Sadd, joined former captain Fernando Hierro in spending over an hour with the World and European champions and their coach Vincente Del Bosque.
The former Real Madrid star, who last played for the Spanish national team in 2006, then signed autographs and posed for pictures with supporters outside the team's hotel.
Raul, who is the Champions League's all-time top goalscorer, is reportedly not the only visitor who the side are expecting before Wednesday's match.
A member of the Qatar ruling family, Al Thani, is also rumoured to be visiting the team at the Torch Doha Hotel.