James Wan's Aquaman was originally set for a release on October 2018, but Warner Bros. has decided to delay the film for two months and has set the release to Dec. 21, 2018.
It might not be that bad of a choice to move the schedule of release since Decemeber next year won't have Aquaman competing with a Star Wars movie; instead, the Han Solo spin-off will be released in May of 2018.
ComicBookMovie also points out that the release date of Dec. 21 was the same as James Cameron's Avatar 2, but since the project was delayed, the date was all up for Aquaman to take. By the time December 2018 rolls in, Aquaman will be competing with the animated Spider-Man movie from Sony.
Here's the synopsis:
Aquaman will center on Aquaman as a reluctant ruler of the underwater kingdom of Atlantis who is caught between land dwellers that are always polluting the globe and his own people who are ready to invade the surface.
Aquaman is directed by James Wan and stars Jason Momoa, Patrick Wilson, yahya Abdul-Mateen, Amber Heard, and Willem Dafoe. The movie is slated for a release on Dec. 21, 2018.