Bottom line
A Mobilization Training Unit (MTU) is a non-pay unit IRR and Standby Reserve Marines can join to drill for retirement points and stay mobilization-ready. You volunteer for it, you commit for a minimum of two years, and you carry real obligations: attend at least 90 percent of scheduled drills, pass your PFT and CFT, keep MCMAP current, keep your SGLI premiums paid, and keep MCIRSA updated on your address, dependents, and job. MTU drills are not paid, but they earn points.
What it means for you
If you are in the IRR and do not want to go cold, an MTU is the structured way to keep contributing and keep earning retirement points. It is volunteer duty in a non-pay status. You apply, you get assigned by orders, and once you are in you are expected to participate at a high rate (90 percent of scheduled drills) and stay within standards. The duty is unpaid, but your participation is tracked for points. One thing to watch closely: if you let your SGLI premium payments fall behind, you are barred from drilling or serving on active duty until you catch up.