If you are interested in volunteering for the IDF without becoming an Israeli citizen, there are a few short-term volunteer programs available.
Volunteer IDF Programs:
Marva: Marva is an army simulation program run by the IDF and Jewish Agency for Israel to give you a taste of what army life is like. After eight weeks in this immersive army program, serving alongside fellow Jewish youth from countries around the world, you’ll know more about the inner workings of the IDF than you ever dreamed, and you’ll have experienced it firsthand.
Sar-El: Sar-El is a three-week volunteer program that enables participants to volunteer and live with Israelis and volunteers from all over the world on army bases in Israel. Volunteers will work alongside or under the direction of Israeli soldiers and perform duties such as packing food rations or medical kits, cleaning tanks, painting helmets, radio repairs, gas mask refurbishment, changing spare parts, gardening, or cleaning.
If you are looking to enlist in the army for a full-time service, visit this page.