StarWars actor Ewan McGregor explains why Yoda hasn't appeared in ObiWanKenobi:
Warning: this story contains spoilers for Obi-Wan Kenobi. "Until the time is right, disappear we will," says Jedi Master Yoda in Star Wars: Episode III – Revenge of the Sith. And disappear, they have. After they fail to destroy the Sith Lords Emperor Palpatine and Darth Vader , Yoda and Obi-Wan retreat into exile: Yoda to the swamps of Dagobah, and Obi-Wan to the sands of Tatooine.
"All he's got left is to look after Luke Skywalker. That's all he's got left, really, and to try to communicate with his old master, Qui-Gonn, in his spiritual life," McGregor said in an interview with The Jess Cagle Show."But he can't reach out to any of his old [mentors]. He can't reach out to Yoda, he can't reach out to any of the surviving Jedi for fear of giving himself away.