There’s a reason why Aquaman is going to be one of (if not the) first movies to take place underwater: it’s extremely hard to do from a technical aspect. Zack Snyder figured it out for Justice League, the action looked great, but there was one aspect that left room for improvement — the dialogue.
The Hollywood Reporter wrote a piece about Aquaman today, and ended it with: “Now, all James Wan and the rest of the Aqua-team needs to work out is how to have all the characters speak while underwater. There can’t be that many air bubbles under the sea, after all.”
In Justice League, when Aquaman and Mera wanted to have a conversation, they had to create an air bubble around themselves, blocking out the water and giving them a space where the actors could talk as normal. It worked for the brief Justice League scene, but it wouldn’t be practical for an Aquaman movie to have the characters constantly surrounding themselves in air bubbles every time they wanted to talk.
Aquaman director James Wan saw the Hollywood Reporter piece and replied on Twitter saying, “Fret not, no ‘air bubbles for dialogue’ in my underwater world.” It sounds like the director has figured out a better way to have the characters talk while underwater. What that solution looks like remains to be seen, but hopefully we’ll find out early next year with the first trailer.