Avatar 4 has officially entered into production. The information has been revealed by James Cameron, who at the recent D23 Expo, gave fans an idea of how each movie is progressing along.
During the Avatar appearance at the event, it was noted that Avatar: The Way of Water is being finished up at the moment, ahead of its release on December 12 this year, and that Avatar 4 has begun its production, which likely means that Avatar 3 is somewhere between these two projects right now.
As for when each Avatar movie, after the second, is expected to arrive, they are planned every other year: 2024, 2026, and 2028, respectively.
Thanks, GamesRadar.