Can i join the marine corps if i have flat feet?

Yes: Having flat feet will not prevent you from joining the armed forces. You should call your recruiting office to find out what is required to be part of the active military.

Maybe: Department of defense medical standards currently state that "current symptomatic pes planus (acquired (734) or congenital (754.6)) or history of pes planus corrected by prescription or custom orthotics is disqualifying." however, the majority of cases of flat feet do not cause any problems, and if you fall in that category you can join the marines, assuming you meet their other requirements.