1. Meet with a recruiter A recruiter can help you understand the process and requirements to enlist in the Marines. Meet with a recruiter in your area to discuss the steps you can take to join. You can find recruiters through the U.S. Marines website or by searching online. To ensure victory for our Nation on every front, Marines must be able to keep up. To that end, these are our physical requirements. Becoming an Enlisted Marine requires the highest standards of moral, mental, and physical strength. See if you meet the requirements to join the Marines. You cannot join the military to enter the U.S. or to get a visa. Age limits. Each branch of the military has age limits to enlist in active duty: Air Force: 17 - 39; Army: 17 - 35; Coast Guard: 17 - 31; Marine Corps: 17 - 28; Navy: 17 - 39; Space Force: 17 - 39; The age limits are different if you join as an officer or join the Guard or Reserve. yRj4e.