On September 22, 2016, a playable version of the full game was accidentally made accessible to those who pre-loaded it two weeks before its intended release date. Nintendo of America quickly took down the pre-load file within hours of this discovery.

Despite the word "Color" being spelt "Colour" in the UK, European copies of Color Splash aren't corrected to have the added "U".

The book that Pry Guy holds is extremely similar to the book Goombella uses to tattle on opponents in Paper Mario: The Thousand-Year Door.

Concept art for Paper Mario: Color Splash shows that the captain of the Violet Passage was at one point going to have a dark skin tone. This would've marked the first instance of a Toad with a distinct skin color (not counting usually-pale Toads under a transformation) in a Mario game, but not the first instance of a non-pale Toad in the Mario franchise as a whole. The Super Mario Bros. Super Show featured a one-off Native American Toad named Pronto, a parody of Tonto from The Lone Ranger, in the episode "The Provolone Ranger".