Daily Yo-kai Watch Factsさんのイラストまとめ

In the Japanese version of Yo-kai Watch 1 for the Nintendo 3DS, the Yo-kai Medallium states that Cruncha can be found on the Mountain Trail in Mt. Wildwood. This, however, is untrue, and Cruncha can only be freed from the Crank-a-kai. This was patched in Ver 1.1 and onwards.

The young boy from Gen Hoshino's music video, I Wanna Be Your Ghost (feat. Ghosts)'s appearance is presumably based on Nate's, due to the theme of the music video, their similar color scheme, and hairstyle. He is also presumably based on Nobita Nobi, from the "Doraemon" series.

The bowls that can be seen in the foreground and background of the Biting Bandits' Song Medal are those of the Yo-kai, Wotchagot and Pride Shrimp.

Despite Walkappa's favorite food being Veggies in Yo-kai Watch 1, it was changed to Sushi in Yo-kai Watch 2, likely to match with fact that Walkappa states that he prefers sushi over cucumbers (which is generally said to be a kappa's favorite food) in the Yo-kai Watch anime.

Harrisville is based off of Kumamoto Prefecture in Japan.

In Episode 27 of the Yo-kai Watch! anime, Whisper attempts to guess Devourer's name upon encountering him for the first time, and while doing so, makes a face near identical to that of the character, Sonic Boom, from the manga and anime series, Ninja Slayer.

Intrudapyon and Abominable Admiral are the only Yo-Criminals that are befriendable in any Yo-kai Watch games, Intrudapyon being befriendable in Yo-kai Watch World, and Abominable Admiral being befriendable in Yo-kai Sangokushi: Kunitori Wars.

Despite Shuten dōji, the yōkai Thurston is directly based off of, being known for being a heavy drinker, Thurston's Yo-kai Medallium Bio in Yo-kai Watch 3 states that the contents of his rice wine cup is a sports drink, due to him losing too many fights while intoxicated.

Harry Barry is based off of the mascot of Kumamoto Prefecture in Japan, Kumamon.