As a prior-service Marine going to Ft. Leonard Wood as a 12B (Combat Engineer), will I have to go through the whole phase of boot camp?

You shouldn't have to do all over basic over again, it would be a refresher course from my understanding. Then you'll go on to AIT to be mosq

I just graduated from D31st there and we had a former marine with us and he was also a combat engineer in the marines and he had to redo all of basic with us because of how long he was out for. So if you haven’t been out too long you’ll go through prior service basic and straight to osut training. From my experience there with the prior service guys.

They should insert you during AIT. Thats what happened to another prior service marine. Who had came in during my training

I think it has more to do how long ago you got out of the Corps. I know some who went right to their MOS school and some who had to go to that service’s boot camp.

Your recruiter should have told you, but not all of us know all the details. I’ve put a few PS Marines in, one straight to AIT, and 1 to week 6 of 19D OSUT. You will know what week you are inserting into on your contract. Both of these guys said the reception week sucked, but once they were in training they were treated like regular NCOs again

SGT, I am a private in the Army and have recently completed infantry basic training and Airborne School at Fort Benning. There was a former marine who I went to airborne with who had been an E 4 and since he had been an Infantryman when he was a Marine he didn't have to go through Basic at all when he enlisted in the Army as an 18x. But he said that he knew of a former NCO in the Marines who joined the Army and had to go through all of Infantry osut. I think that was either because he hadn't been an Infantryman when he was in the Marines or it might have been because he was out of the service for too long. But that might just be something that they do at Fort Benning. I hope this helps SGT