Gorgeous merfolk, magical fountains, malicious pirates, overweight kings – it’s all in a day’s work for Johnny Depp’s Captain Jack Sparrow, who will return to theaters once more in next summer’s Pirates of the Caribbean: On Stranger Tides.

Contest winners that attended the “Pirates Fans First!” party got to check out all the swashbuckling action in the first theatrical trailer for Disney’s fourth Pirates of the Caribbean on the big screen in all its 3D glory – and now that teaser is online for everyone else to see as well.

Franchise writers Ted Elliot and Terry Rossio went the Thoreau route (“Simplify, simplify”) and crafted their screenplay for On Stranger Tides as a stand-alone venture featuring Captain Jack, much like the first entry in the series, The Curse of the Black Pearl. Whereas that film revolved around villainous buccaneers cursed with immortality (being undead and all), next year’s POTC flick finds the lovable but incorrigible Jack Sparrow on a quest to avoid his inevitable demise by finding the legendary Fountain of Youth.

Along for the ride this time are series veterans Geoffrey Rush and Kevin R. McNally as Captain Barbossa and Joshamee Gibbs, respectively; newcomers Penelope Cruz as Jack’s old flame, Angelica, Ian McShane as her dad, the pirate Blackbeard, and Astrid Berges-Frisbey as a mermaid named Syrena, a lovely but mysterious sea creature who plays a pivotal role in the plot of On Stranger Tides.

Check out the Pirates of the Caribbean: On Stranger Tides trailer (courtesy of Box Office Spy) below:

On Stranger Tides looks to offer much of what worked well in the first three POTC flicks (Jack’s witty quips, fast-paced action involving swords, steel, and explosions) and overall appears less overblown in tone and design that the last two films in the series. Director Rob Marshall has handled big-budget fare before and seems to have struck a visual chord with the fourth POTC flick that both resembles that of Gore Verbinski’s trilogy and is distinct in its own right.

There’s also something to be said for the use of non-CGI supernatural creatures, as the zombie creatures (?) and mermaids in this trailer look all the better and more realistic because they’re actors/actresses with makeup and costumes on. Finally – having a dirty, heavily-scarred human villain like McShane’s Blackbeard onboard seems a wiser choice than having another ultimately kind of goofy-looking bad guy, a la Davy Jones and his squid beard.

Pirates of the Caribbean: On Stranger Tides arrives in 2D, 3D, and IMAX 3D theaters around the U.S. on May 20th, 2011.