Essentially OCC is for college graduates and PLC is for those still in school. See my brief breakdown below: OCC: -Go after college -Train for 10 weeks -Commission -Report to TBS immediately The cons of OCC are that selection is more competitive and the 10 week straight course length. PLC: -Go during college -Train for two 6 weeks periods over summer (or one 10 week for PLC Combined) -Commission after college graduation -Report to TBS in a few months The cons of PLC are the two 6 week periods of summer you spend training and the length of time between college graduation and TBS. I know some guys that had to wait over year before going to TBS. The average wait time though is around 4 months. I'd check out https://www.marines.com/becoming-a-marine/officer.html for further information as well.