 | Jason Momoa | .... | Arthur |
 | Amber Heard | .... | Mera |
 | Willem Dafoe | .... | Vulko |
 | Patrick Wilson | .... | King Orm |
 | Nicole Kidman | .... | Atlanna |
 | Dolph Lundgren | .... | King Nereus |
 | Yahya Abdul-Mateen II | .... | Manta |
 | Temuera Morrison | .... | Tom Curry |
 | Ludi Lin | .... | Captain Murk |
 | Michael Beach | .... | Jesse (Manta's Father) |
 | Randall Park | .... | Dr. Stephen Shin |
 | Graham McTavish | .... | King Atlan |
 | Leigh Whannell | .... | Cargo Pilot |
 | Tainui Kirkwood | .... | Young Arthur (Three Years Old) |
 | Tamor Kirkwood | .... | Young Arthur (Three Years Old) |
 | Denzel Quirke | .... | Young Arthur (Three Years Old) |
 | Kaan Guldur | .... | Young Arthur (Nine Years Old) |
 | Otis Dhanji | .... | Young Arthur (Thirteen Years Old) |
 | Kekoa Kekumano | .... | Young Arthur (Sixteen Years Old) |
 | Julie Andrews | .... | Karathen (Stimme) |
 | John Rhys-Davies | .... | Brine King (Stimme) |
 | Djimon Hounsou | .... | King Ricou (Stimme) |
 | Andrew Crawford | .... | Brine King & King Ricou |
 | Sophia Forrest | .... | Fisherman Princess |
 | Natalia Safran | .... | Queen Rina |
 | Micah D. Ohlman | .... | Newscaster |
 | Jack Andrew | .... | Mike (Bully) |
 | Frankie Creagh-Leslie | .... | Matt (Bully) |
 | Sophia Emberson-Bain | .... | Tour Guide (Aquarium) |
 | Ilya Melnikoff | .... | Submarine Captain |
 | Hank Amos | .... | Submarine Pirate |
 | Kyryl Koltsov | .... | Submarine Crew Member |
 | Patrick Cox | .... | Cue Ball |
 | Luke Owen | .... | Biker |
 | Robert Longstreet | .... | Professor James |
 | Devika Parikh | .... | Newscaster Morgan |
 | Sonny Le | .... | Metalsmith |
 | Jon Fabian | .... | Italian Vendor |
 | Mabel Tamone | .... | Italian Young Girl |
 | Rita Dinardo | .... | Italian Old Woman |
 | Anthony Standish | .... | Barfly |
 | Nicoletta Bianca | .... | Italian Mother |
 | Victor Leto | .... | Flower Stall Vendor |
 | Vincent B. Gorce | .... | Italian Bell Father |
 | Gabriella Petkova | .... | Italian Bell Girl |
 | Oriana Iacono | .... | Italian Bell Mother |
 | Pearl Alice Grantham | .... | Ancient Atlantean Woman |
 | Noa Tsuchiya | .... | Ancient Atlantean Child |
 | Alice Lanesbury | .... | Arthur's Teacher |
 | Nicolas Bosc | .... | Atlantean Soldier #1 |
 | Joshua Levinson | .... | Atlantean Soldier #2 |
 | Patrick Atchison | .... | Russian Submariner / Ancient Atlantean / Beachgoer (uncredited) |
 | Kalani Bell | .... | Arthur's Class at Aquarium (uncredited) |
 | Will Bergman | .... | Village Mayor (uncredited) |
 | Brendan Byrne | .... | Beachgoer (uncredited) |
 | Leo Castro | .... | Italian Fish Monger (uncredited) |
 | Harry Cummins | .... | Beachgoer (uncredited) |
 | Sasha Dulics | .... | Waiter (uncredited) |
 | Andy Esho | .... | Sicilian Villager (uncredited) |
 | John Gettier | .... | Submarine Crew (uncredited) |
 | Daniel Goodwin | .... | Russian Submariner (uncredited) |
 | Bailey Hendy | .... | Atlantean Warrior (uncredited) |
 | Tahlia Jade Holt | .... | Atlantean (uncredited) |
 | Lane Howson | .... | Beach Goer (uncredited) |
 | Wayne Huang | .... | Modern Atlantean (uncredited) |
 | Beau Jones | .... | Fisherman (uncredited) |
 | Ross Kernahan | .... | Ancient Atlantean (uncredited) |
 | Braden Lewis | .... | Beachgoer (uncredited) |
 | Jordan Lewis | .... | Ancient Atlantean (uncredited) |
 | Niam Mayes | .... | Tourist (uncredited) |
 | Salvatore Merenda | .... | Bar Patron (uncredited) |
 | Marco Minici | .... | Delivery Man (uncredited) |
 | Sam Monaghan | .... | Russian (uncredited) |
 | Rhianna Palmer | .... | Bar Patron (uncredited) |
 | Kai Pantano | .... | Commando (uncredited) |
 | Anna Patch | .... | Atlantean (uncredited) |
 | Sam Price | .... | Atlantean (uncredited) |
 | Jon Quested | .... | Russian Sailor (uncredited) |
 | Jon Reigle | .... | Atlantean (uncredited) |
 | Bella Rose | .... | Arthur's Class at Aquarium (uncredited) |
 | Thomas Sebecke | .... | Russian Submariner (uncredited) |
 | Bobby Silva | .... | Modern Atlantean (uncredited) |
 | Rafael Torrijos | .... | Beach Goer (uncredited) |
 | Mikey Wulff | .... | Ancient Atlantean (uncredited) |
 | Connor Zegenhagen | .... | Russian Submariner #2 (uncredited) |