This is only made for kids, but there would be nothing wrong with an adult wearing one if it was available in adult sizes. Nothing though is really stopping you from creating your own fashion company and manufacturing an adult-size turtle costume, except all the logistics, time, effort, cost, taxes, import fees, licensing, and headaches involved in creating a company for the sole purpose of making one adult size turtle costume.

DETAILS:
Body is made from 100% cotton t-shirt fabric 

ykk hidden front zip

shell is made from poly stretch velvet 

Size XXS best fits ages 6 - 12 months

Size XS best fits ages  18 months-2 years

Size S best fits ages 2-3

Size M best fits ages 4-5

Size L best fits ages 6-7

Size XL best fits ages 8-9