Why do u think they don't wear pants.

They're ponies.

Besides, why would they wnat to cover up their Cutie Marks!?

Honestly, if u were a My Little Pony, would u wear pants?

They don't need pants. If they wear clothing, it's only for looking extra special, and a dress of tux is best for that.

Pants would look awkward on them. I'm trying to imagine it, and it just doesn't work with their body shape.

Cutie Marks, baby! It's a major part of their identities, so they wouldn't want to cover them up.

i have a few reasons

1: theyre ponies, and like appeldrank, applejack said, they dont normally wear clothes, and the only time i can remember a pony wearing something was if it was some kind of formal attire, like a suit of a dres.

2: the putting on of pants would be pretty hard for ponies considering they dont have fingers to button the buttons, of zip up the zippers (ma ybe they can wear sweat pants, i dont know). And wearing pants would imply the use of pockets, and ponies either use saddlebags to carry stuff in saddlebags of just pull whatever they need out of nothing, because thats how cartoons work.

3: this one is a little PG. The reason humans wear pants is to cover up certian "things" and from watching the show, its quite obvious that ponies dont have these "things" and so theres not really any reason for them to wear pants.

They-a don't-a usually wear clothes, u know. But-a that kinda gets-a me, too.

There is a scene (I think it's in "Green Isn't Your Colour" but I'm not certain) where Fluttershy is wearing an all-in-one type of outfit, where her whole body is being covered up (including all four of her legs). Looks like it would have been awkward to put on though! Not like the dress-type clothes they sometimes wear, which they can just slip right into.

Same with the Wonderbolts' clothes. Their back half is covered up, but I always thought they don't look very comfortable somehow. I think that the reason the characters usually only cover up their front half is because it's not too complicated for them to put on.

Besides, they have nothing to hide! XD