what is avatar 4 going to be called

The most widely reported answer is that Avatar 4 does not have an official title yet ; it is still being referred to simply as “Avatar 4.”

What people are calling it

A few fan and entertainment outlets have floated names like “The Tulkun Rider,” but those are not official confirmations from Disney or James Cameron.

What is confirmed

The film is still scheduled as the fourth installment in the franchise, with a release date currently listed for December 21, 2029.

Bottom line

So, as of now, the safest answer is: no official title has been announced for Avatar 4 yet.

TL;DR: It’s still officially just Avatar 4 for now.