if so i would like to know the date ^_^ thanks.

Maybe in Japan but probably not.
Neon Genesis Evangelion
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RE:

Is there a such thing as national anime day?

if so i would like to know the date ^_^ thanks.
In Japan is National Manga Day at November 3rd. And almost every anime is adaptation of manga, so you can make in one-and-half month some celebration. 🙂
Sadly,no.But,you can declare it national anime day anytime you want. I make anime day everyday.
i think not but it would be cool if there were