The 23-year old South Korean international has been linked with a number of clubs in recent times with German pair Bayer Leverkusen and Werder Bremen and Russians Rubin Kazan at the forefront of those showing interest.
But Ki says he would prefer a shift to Spain's top flight, however, he would only make the move if he was guaranteed first team football.
"Ever since I was a kid I have dreamed of playing in the Spanish league," he told Record Sport.
"I would only move from Celtic if I am guaranteed playing time but if and when the offer comes I hope it is from Spain.
"All footballers want to play at the highest level and my ambition is to play in La Liga.
"We won the SPL this year and that fulfilled my hopes in Scotland.
"Now I have to wait to see if I am transferred."