How can i dye my swimsuit into a darker color? Posted on September 29, 2010 by Baday I would like to dye my swimsuit but i dunno what percent the spandex is coz the tag already faded. The suit fits me very well, and I’d like to dye it in a darker color (black or dark blue) so that I can wear it during my swimming class. We’re not allowed to wear bright swimsuits like neon colors. Btw, the color is neon pink. What kind of dye should i buy? Thanks.