With careful planning, you can take two full years of transferable coursework at a community college and graduate two years after transferring to UC. The key is taking only courses that are acceptable for transfer credit.
California community college has an agreement with UC. It's called a transfer
course agreement (TCA). The TCA specifies which of its courses receive UC
Plus, your community college and the UC campus you wish to attend may have additional agreements that specify which transferable courses may be used to meet various college (general education or breadth) and major requirements.
Limits on transfer credits
UC awards graduation credit for up to 70 semester (105 quarter) units of transferable lower division (freshman/sophomore level) coursework from a community college. That means those units will be counted toward completion of your degree. Courses in excess of 70 semester (105 quarter) units will not receive unit credit but will receive subject credit and may be used to satisfy UC's subject requirements.
Some campuses also limit the total number of transfer units that will be accepted. If your lower division work is combined with credit from a four-year institution, different unit limits may apply. Please consult the admissions office at the UC campus that interests you.
See UC's Statement of Transfer Practices [PDF] for more information on transfer credit limitation.
Transfer from semester to quarter system
All UC campuses use the quarter system except UC Berkeley and UC Merced, which use the semester calendar. If you are enrolled in a community college or other institution with a fall term that does not end before January 1, you cannot transfer to UC for the winter quarter.
Most students don't lose credit when they transfer. If you will be changing from a semester to a quarter system, you should try to complete series courses before you transfer — for example, Chemistry 1A-1B — to avoid duplicating coursework. If your school is on the semester calendar and you wish to enroll in the latter terms of a two- or three-quarter course sequence at UC, you may have to repeat material.
All transferable units will be converted from semester to quarter units, except at UC Berkeley and UC Merced.
Active-duty or veterans of the U.S. military who have completed courses provided by the military (not courses completed at a collegiate institution) should inform UC of such in the comment box on the admission application. Students should be prepared to submit official military transcript (e.g. SMART, AARTS, etc.) after enrollment at UC.
UC may award transfer credit for some of your military courses if the content was equivalent to a course taught at the University.