https://www.gameinformer.com/gamer-culture/2018/11/02/the-next-four-avatar-movies-reportedly-have-titles
Lightstorm Entertainment

Remember when Avatar was the biggest thing in the world and you couldn’t escape the blue people and mentions of 3D movie theaters? The people behind the movie remember, which is why there’s four more movies currently scheduled. While there were assumptions they would just be called Avatar 2, 3, etc., it seems like James Cameron is going with unique titles for each movie.

According to a Tweet from the movie ticketing site Fandango, which itself sources the BBC, the titles are The Way of Water, The Seed Bearer, The Tulkun Rider, and The Quest for Eywa.

As the tweet mentions, the first sequel, The Way of Water, releases at the tail end of next year, two days before Star Wars: Episode IX. Both that movie and The Seed Bearer have already been filmed, with The Tulkun Rider and The Quest for Eywa currently in production.

The first Avatar film made $2.7 billion worldwide.