Do go to a music store and try them out. Music and Arts let my son try out a few instruments and he picked the trombone. They were really nice about it. Don't rule out percussion too. For the drum kit, there is some natural ability involved. You can see videos online. But, there are other instruments the don't take a lot of ability.

The thing with the slide is true of most kids. Kid music doesn’t use the slide position all the way out very often (plus kids often make it fall out lol). No worries there.

My kids play tuba and baritone. The size isn't generally an issue because they have a school instrument and a home instrument that we rent. I do, however, agree with the PP that the trombone is more flexible for different types of ensembles.

Go to a music store and try out both to decide.

Trombone would be more flexible -- wind ensemble, marching band, orchestra, jazz, brass quintet all have trombone parts

my ds started trombone in 4th grade then switched to baritone in 6th grade. the instruments are very interchangeable. for those suggesting trumpet, the mouthpiece is enough different than trombone/baritone so if the teacher thought trombone/baritone best, I would go with that suggestion. does the school have a baritone he can use at school so he doesn't have to transport it back and forth each day so you only need to rent one for home practice? given my ds smaller size, carrying his huge backpack plus his trombone was an issue so if he had stayed on trombone we would have needed to get a second one to leave at school. don't let his size guide your choice. they are both great for a smaller kid. let him decide which he prefers. go to a music store like l & l music where they will let him try out both for as long as he wants to see which he prefers.

My kid is not particularly gifted in music, and he picked up trombone faster than I would have thought. It's a cool instrument! But yes, I agree, let him choose!

I have a couple of brass players, one trumpet and one trombone. Both kids occasionally fill in on a school-owned baritone, so it doesn't seem that it is too difficult to switch between them. Trumpet wins for easy transport and lower cost, but the trombone is certainly manageable. Let him choose and start on a rental or borrowed instrument so that it is not a problem if he decides later that he wants to switch to a different instrument.

Trombone is way cooler and plays more melody. Also easier to transport.

I would add trumpet to his list and let him pick. Actually, if he would rather play a woodwind or percussion, let him pick that. He'll enjoy it more if he plays what he wants to play.

My older sister switched from flute to baritone in high school and easily mastered it. It may be one of the easier brass instruments.

My kid is small and played a big, heavy brass instrument. Go for the Trumpet. 10000x easier to transport. Unless he won’t need to carry it back & forth, then go for it.

OP here. I’m not exactly sure what was involved in the placement testing they did in school, but trombone/baritone was recommended first, followed by trumpet. He indicated that the shape of their mouths and ability to make sounds on the mouthpieces was the primary consideration. Clarinet was not on his recommendation sheet, so not sure about that. As for what he wants to play, he is pretty open and doesn’t have a strong preference.

The clarinet would be the easiest for an “uncoordinated” child. The half presses would be hard on a trumpet. How did your child play on the recorder?

The one he wants to play.

Either will be fine but if he is small, and not the greatest coordination, why not Trumpet? That's a smaller mouthpiece and bore, and much easier to handle. And, if I may add, way cooler!

My 6th grader is in beginning band and wants to try an instrument for the first time. After initial testing with mouth pieces, the band director says his mouth is best suited to the trombone or baritone. Does anyone have any experience with these instruments and how difficult they are to learn how to play? He is a small kid, so the baritone seems big/heavy; however, his arms are barely long enough to reach all the way out with the slide on the trombone, so that could pose some difficulty. This is a kid who is very smart but not particularly coordinated. Any advice on which instrument might be the best fit?