What I heard and based on my own research (I was considering this route before the application season just in case results do not come out nice, but in my case I ended up well) you have to finish the “GE” requirements to transfer. Here is a link to the specifics: http://admission.universityofcalifornia.edu/transfer/preparing-admission/minimum-requirements/index.html
I’m just a graduating HS senior, but I am just giving you the info that I found for myself when I was considering this route. Good luck!