Alves has joined on a four-year deal.
The 25-year-old Brazilian, who could not save Almeria from relegation in the recently-concluded Primera Division season, is excited at the move.
He told valenciacf.com: "I have fulfilled a dream by signing for a big European club in the Champions League.
"Valencia have been my goal ever since I knew of their interest.
"I arrive with desire, ambition and humility and look forward to giving everything for the club and their fans."