The goalkeeper has had hit contract terminated by mutual consent after being banished to the reserves this season.
Valles and Las Palmas fell out as he sought a move away last summer.
While now a free agent, Valles aims to join Real Betis next season with their registered squad list now full.
He told Radio Marca: "For me it's something to be grateful for that they are there and always have me in mind. I don't have to hide, everyone knows that Betis is the club of my life, the club of my city and that I would love to be linked to Betis at some point in my career."
On Las Palmas, Valles also said: "You have to understand both parties, each has their reasons. They defend what is theirs, which is the club and the ownership, and I, my career and my future.
"I am a person who, when I make a decision, I make fixed decisions and when I believe that something is right for me and my family, I do not usually back down. I always look forward.
"The club did not want to prolong it any longer and I had no special interest in prolonging this situation that was not being easy. An agreement was reached with them and the decision was made to terminate, and each one takes his own path."