The TL;DR is that the GTA 5 Online pirate frontier outfit comes in seven different pieces, and you’ll need to find various shipwrecks scattered around the map and open treasure chests to get them.

Not every cache contains a piece of the outfit, though you’ll get other rewards — $20,000 and 2,000 RP each — for your efforts if not. We’ll have a whole guide on how to find all 30 shipwrecks very soon and will link it here. 

Per Rockstar, “only one shipwreck can be found per day [and] you can track whether you’ve found today’s shipwreck via the Daily Collectibles section of the Interaction Menu.”

You can change into the pirate frontier outfit just like you change into any other piece of attire in GTA 5 Online: either in the clothing store or your wardrobe. And that’s that. For more, consider giving our other GTA Online guides a look!