Is it possible to serve in multiple branches of the military ?

yep, did it. Joined the USARMY as a medic. After basic at fort sill I was supposed to be at Ft leninwood... but the Army needed FDC more than medics so I was reassigned. After 5 yrs of that I transitioned to Tach-medical-evac in the USAF. Spent most of my time in the field. Transitioned to USSOCOM and it was like being back in the Army. Pulled a tdy on the USNS Mercy in California. So think of it...Army trained, USAF e-8 serving on a ship.

My take is that joining our Armed Forces simply to satisfy an urge to be a "jack of all trades" is a pretty selfish motive. It indicates no knowledge of, or concern for, the brotherhood/sisterhood of the American Patriot who serves his/her Country because of a feeling of gratitude and respect for Her. There is no respect or commitment to compatriots, no dedication to anything but personal satisfaction and telling people "look what I did"... This is a far cry from people, and I have known some, who entered one branch of military service and at some point after being discharged entered another branch for reasons that were for the good of the Country, and not a personal whim. I expect that some people will not agree with my opinion, and that is just fine... understand that my reply is based on the original reasoning posted for enlisting, and my personal views regarding respect and honor, to which I am entitled.

USAF and US Army (NG)

I've served in the air force, army and currently air guard. The switches were easy. Going from active duty to guard was a diffucult transition because us prior service do most of the work, know our jobs and get promoted after the people who don't know their jobs. I'm switching to the reserves next. Each branch has its good and bad.

RM1 as a retired USCG I also served in USN and USAF that's 3 upon discharge from USN I joined
USAF lost time in grade but kept grade but was REQUIRED to take and pass all training up to E-5
or be rifted to E-4 it wasn't easy and just made it. upon discharge from USAF enlisted in USCG but
the only reason I was able to do that was because of my prior job in USN. I also had to get a waiver
from Washington and also lost time in grade. So check everything out before you jump!

It is possible, but I personally wouldn't recommend it. I served 4 years and some change in the army then got out for 3 years. I then re entered the military, this time Air Force and have been in for 14 years with the AF. The benefits are all the same in every branch, but the mission and life is drastically different. I would focus on what type of lifestyle or job you really want and stick with it. It can hurt your promotion timeframes switching services. I also wouldn't go from the cushier branch (airforce) to the army or marines, just because the mission is completely different. I may be impartial being an ex recruiter, but the quality of life in the AF has been in my opinion, a lot better than other branches. Best of luck.

There is a second line to that adage jack-of-all-trades, it is master of none! Before you go and think about all the things you want to do, pass basic training in the army and mastering your own skill then and only then will you be able to go to a different branch or A different MOS.

I don't what the rules are currently, but my first 4 years were Air Force 30351 ATC radar repair tech. 8 months after honorable discharge, I joined the Army 11B7V. Airborne Infantry. Retired after 16 years, for a total of 20 years.

I have in my twenty-six years in the Marine Corps met exactly one person who served in all four branches, the Marine Corps being his fourth. I cannot recall how many totals combined years of service he had accumulated; I'll guess eighteen for argument sake. So, here's the problem, let's say you served five years in each branch a total of twenty years and obtained the paygrade of E-5; yay, you accomplished your goal, but are retire as a Marine Corps Sergeant, I am assuming because is the last branch you served in and retired. Congratulations now you draw E-5 pay over twenty years ($1,700 per Month) instead of possible E-9 pay over twenty ($3,000 per Month). Good luck! And I am not even sure it would be possible today, and even if it were, I would not recommend it. The only upside you can call yourself "Marine" Sorry, I could not restrain myself, LOL!

When I was on Recruiting tour the Army still had the Split Option Program where 17 year old High School Juniors could go to basic before their senior year. It sold like hotcakes, even my own son went to basic and was in a Reserve unit. I got six in one month. Unfortunately the powers that be, decided that these soldiers could enlist in any of the other services as an initial enlistments but the Army had to treat them as Prior Service. We were out of the market, as far as Recruiting Command was concerned I had betrayed them