Aquaman, which stars Jason Momoa in the title role, has received mixed reviews from critics.
After two brief appearances in Batman v Superman: Dawn of Justice and Justice League, the king of the undersea nation finally has his own origin story.
While some reviewers said the blockbuster was a bit of a bore, others thought it was quite entertaining.
"It's refreshing to see a hero that doesn't take himself so seriously," said James Luxford in The Radio Times.
"From his action packed, slo-mo heavy introduction aboard a submarine, it's clear that entertainment is the main priority instead of universe building.
"It's tempting to dismiss this high concept chaos as just another bad superhero movie, but amid the ocean of CGI and a patchy script there's a lot of fun to be had."
In his three-star review for The Mirror, Chris Hunneysett wrote: "The sixth instalment of the DC Extended Universe swims into cinemas on a high tide of stunning CGI and waves of superhero comic book action."
"Surviving on a drip feed of romance, our leads are thankfully drowned in a tsunami of Avatar-quality visuals which sees armies, herds and shivers of giant armoured sea creatures battle in an impressively epic finale."
The Independent's Geoffrey Macnab said: "Aquaman is the cinematic equivalent of bouillabaisse - a fish stew of a superhero movie into which every available ingredient has been thrown.
"Bits of it are hard to digest, bits are flaky, but it has plenty of flavour.
"It is rousing fare, made with enough conviction for it to get away with its moments of extreme kitsch silliness."
Robbie Collin gave the film two stars in his review for The Telegraph, writing: "A film you sense would have worked best as a flashy, froth-tossed romp feels lumpily overburdened, and pulled in all directions by vying currents.
"It's put together with so little consistency that even individual shots look like their various parts have been thumbed together like bits from mismatched jigsaws.
"Momoa and Heard rarely connect as actors across the green-screen void, and the storytelling bears the scars of the copy and paste keys."
Empire's Helen O'hara said: "The plot is honestly a mess: over-complicated yet predictable. What makes the film passably entertaining is that director James Wan throws astonishing amounts of action at the wall, and much of it sticks (though not always together).
"There's entertainment in watching something so outrageously over-the-top, exploding in such strange ways.
"Just when you think you have a handle on it, something bizarre will happen.
"Momoa takes every inch of space the film gives him and runs a mile on sheer roguish charm, and Wan is a sufficiently gifted action director not just to keep you watching but to regularly dazzle you."
The Guardian's Peter Bradshaw called it "a complete bellyflop" in his two-star review
"A laborious, slow-moving and dripping wet film, barnacle-encrusted with solemnity and with a ripply-underwater production design that looks like a giant version of the kitschy items that you put in fish-tanks," he wrote.
"Momoa's good-ol'-boy characterisation of Aquaman itself only goes so far. This is a film that never quite comes up for air."
Digital Spy's Hugh Armitage said: "Aquaman is a flawed but thoroughly entertaining adventure movie and certainly one of the strongest instalments so far in the inconsistent Worlds of DC franchise."
"One of the movie's strengths is that its cast understands the sort of film they are in, and don't take themselves too seriously.
"Aquaman also gives Worlds of DC one of its best finales, a grand CGI battle unusually coherent both in terms of the action and its connection to the film's story."