Costume

Costumes (コスチューム) is a term used to refer to distinguishing outfits worn by Heroes and Villains.

Heroes
Pro Heroes and Student Heroes alike often requite specific battle wear to fight and properly use their Quirks. Hero costumes are necessary gear to help Pro Heroes do their jobs most effectively, reducing risk to themselves while increasing their efficiency.

Costumes are generally tailored specifically to the hero in order to amplify their abilities and weaken their drawbacks. They also help the public recognize them and distinguish themselves from other heroes. Women often wear bodysuits. Support companies and genius scientists are the masterminds behind creating costumes for heroes.

Professor David Shield is one of the most well-known costume designers in the world. He designed all four of All Might's costumes during his run as the No. 1 Hero. It’s the support of these costumes that allows All Might to fight at full power without risking damage to himself or his clothing. Other heroes also require additional support items to further aid them.

For student heroes at U.A. High, costumes are developed at the school's expense. Costumes receive alterations throughout a student's career as they learn more about themselves and their Quirks. Alterations and support items are added by Power Loader in his development studio.

Mirio Togata's costume was designed to help him use his Quirk without losing his clothes. His costume is lined with fibers created from his hairs. This is just one specific way costumes help student heroes deal with their weaknesses.

Villains
While Heroes are welcome to proudly don their costumes, Villains do not have access to support items via legal channels. Villains generally use costumes as a way to hide their identity rather than distinguish themselves like Pro Heroes.

Support items and villain costumes are sold through the black market using brokers like Giran. He provided the Vanguard Action Squad with the proper gear to help support their Quirks. Himiko Toga received the most dramatic change in costume. Her equipment functions to help her gather blood for her Transformation Quirk. While other costumes, like Dabi's seem to be completely cosmetic.