Another outlet supports evidence that Jason Momoa will rock a more comic-faithful Aquaman outfit in his standalone movie than he did in Justice League. In addition, it also seems that the events of Justice League will be explicitly referenced.
According to Jeremy Conrad of Furious Fanboys, Aquaman is indeed a sequel to Justice League as it was intended to be in the first place, and that the events of that movie — and specifically the fact that Aquaman helped repel an alien invasion — are explicitly referenced in the movie. But perhaps more interestingly, is that the film may feature our hero saving the day in his original outfit:
Aquaman does have his classic look in the movie. Gold tunic, green pants and gauntlets.
— Jeremy Conrad (@ManaByte) February 21, 2018
While Aquaman’s design in Justice League was fairly close to his appearance in the comics, director James Wan wanted his film to emphasize that the character’s story arc over the course of that film and the one he’s in charge of is to show Arthur Curry’s transformation from a reluctant, abrasive loner to a clear leader to his people — and naturally, one can never go wrong with returning to the basics to demonstrate that point.
Aquaman will be released on December 21, 2018. Its cast includes Jason Momoa as Arthur Curry (Aquaman), Amber Heard as Mera, Willem Dafoe as Nuidis Vulko, Yahya Abdul-Mateen II as Black Manta, Temuera Morrison as Thomas Curry, Dolph Lundgren as King Nereus, Patrick Wilson as Prince Orm Marius (Ocean Master), and Nicole Kidman as Queen Atlanna.
Source: Jeremy Conrad