Worn by: Ed Harris as Virgil "Bud" Brigman
Reference: Seiko Diver
Brand: Seiko
Team leader Virgil "Bud" Brigman appropriately wears a sturdy Seiko ref. 6309 divers' watch in James Cameron's blockbuster about a diving team attempting to retrieve a lost nuclear submarine when they encounter an otherworldly presence at the bottom of the ocean. Nicknamed "Turtle" for its cushion-shaped case with rounded corners, the watch has been around in some form since 1976 and has become one of Seiko's most enduringly popular divers' watches. The modern SRP versions feature hefty 45mm cases and 200-meter water resistance.
Source: https://teddybaldassarre.com/blogs/brands/movie/references/watches