He held a rally in front of a packed crowd at Ventura College at 1 p.m. After stepping up to the podium, Sanders called out Donald Trump, saying he "can't wait" to have a one-on-one debate with the Republican candidate.
"I think I am going to have to rent out the largest stadium you have here in California," the Vermont senator said.
Thousands cheered for Sanders, excited about his plan to make tuition free at public universities and colleges like Ventura College.
"Why in God's name are we punishing people for getting an education? We should be rewarding them, not punishing them," he yelled, in front of the lively crowd.
Sanders added that he would propose a tax on Wall Street to fund a free-tuition program and predicts people would be happy to support it.
In a one-on-one interview with Eyewitness News, Sanders reacted to Hillary Clinton's decline to debate him.
"I'm disappointed. You know, I think if you're running for president of the United States, you should be prepared to have a very serious debate in the largest state in our country on issues that are important. It's, I think, kind of insulting, if I may say so, to the people of California."
When asked what the public's biggest misconception is of him, Sanders said he's sweeter than he looks.
"That I'm a grumpy old man, and I'm not," he laughed. "I sometimes smile."
Sanders also spoke at Ganesha High School in Pomona as speculation mounted over the possible debate between him and Trump.
"I think the American people want to really hear a debate from two people whose views could not be further apart," he said.
Sanders was scheduled to appear on the "Jimmy Kimmel Live!" show.
On Wednesday, Trump appeared on the show and said he may consider debating Sanders as long as money goes to women's healthcare. Sanders said he would fund veterans charities.
Not long after the segment aired, Sanders tweeted "Game on" and that he looks forward to debating Trump. It is unclear if the two will in fact debate one another.
Sanders, Hillary Clinton and Trump also campaigned in Los Angeles and Orange counties. Clinton was at a union headquarters in Buena Park, Trump spoke at a rally in Anaheim where protests erupted and Sanders appeared in Lancaster and Riverside County.