Shorts

Splatoon

In Splatoon they are not changeable and always have the same appearance: black, with a stripe of the wearer's ink color on either side. The male Inklings' shorts are slightly longer than the females', and go down to their knees. They have no other role in the game whatsoever. The only gear that does not have the standard shorts are:

Gallery

Two Inklings wearing the shorts.
The back of them.
The shorts.
The SQUID GIRL Gear has no shorts when worn by a female inkling.
This image shows that shorts, at least for female inklings, have pockets.

Splatoon 2

In Splatoon 2 pants are now available as default customization options much like hairstyle, eye color, and skin color. Shorts can be changed into different types, including skirts with shorts, capris, leggings, and exercise shorts as well as loose shorts with leggings, looser capris, leggings lacking shorts, and loose shorts reaching just below the knee for boys other than their normal Splatoon shorts. Unlike regular Gear, shorts act similar to skin color, eye color and hairstyles, in that they are simply cosmetic.

In the Version 2.0.0, four new styles were added, the "Tight black pants" and "Loose sport shorts" for girls, and the "Leggings" and "Denim shorts" for boys.