Jason Momoa specifically requested Temuera Morrison, one of Momoa's acting idols, for the role of Arthur's father Tom Curry.
Numerous underwater waterfalls are seen in this movie. This is an actual phenomenon. The ocean is made up of two different layers of water: warm, light water, and cold, dense water. The difference in densities means the layers are separate and causes the heavier cold water to fall, forming a waterfall.
Arthur Curry (Jason Momoa) and his father Tom Curry (Temuera Morrison) are portrayed as being of Polynesian nationality, with Momoa being Hawaiian and Morrison being Maori. Momoa has said that he was proud of making Aquaman a Polynesian, as Polynesians have a strong aquatic heritage.
During the duel between Arthur (Jason Momoa) and Orm (Patrick Wilson), an octopus plays a drum solo. According to writer and director James Wan, this octopus is Topo, Aquaman's octopus sidekick from the 1950s and 1960s, who was able to play musical instruments. Wan was initially unsure about putting Topo in this movie, but was inspired to do so after watching Mad Max: Fury Road (2015), saying, "If that film could have a guy playing a flaming guitar, I'm going to have an octopus drummer in mine."
Nicole Kidman immediately accepted the role of Atlanna when writer and director James Wan said that she could wear "Mother-of-Pearl and be a Mermaid Warrior."