Following the pattern of previous games in the series, there are several Far Cry 6 endings to unlock, including a jokey 'best' ending. This secret ending is easily missed, however, so pay attention to the game's opening hours if you want to access it. There's really only one true canonical ending in Far Cry 6, but before we get into that, consider this your one and only spoiler warning.
Ready? Let's dive into the Far Cry 6 secret ending, and all the other conclusions.
Far Cry 6 endings
There aren't many choices to make in Far Cry 6, so your ending is pretty linear. You'll need to be Rank 11 or higher to succeed in the final missions, so make sure you do Yaran Leader quests, treasure hunts and lots of fighting to up your rank beforehand. By this point, we know that Castillo is acutely unwell—with cancer that cannot be treated by Viviro—and will not let himself or Diego be captured by guerrillas. After a short monologue, he shoots Diego in the chest and slits his own throat.
In the end, Dani gets to choose whether they or Yelena get to become El Presidente in Castillo's wake. Ultimately, Dani refuses, telling Yelena "Yara is yours. Don't fuck it up." She becomes the de facto leader of Libertad and once the credits roll, you'll be able to get back to fighting the remainder of Castillo's forces.
Far Cry 6 secret ending
Unlike Far Cry 5, where the secret ending was available in the game's opening sequence, you'll need to play for a few hours before this one becomes available. When you reach Clara, Dani will say that she wants a boat to travel to Miami in exchange for helping Libertad. Clara agrees and you'll be able to play through the Libertad missions.
Once you've established Libertad HQ and destroyed Castillo's boats, Clara will uphold her end of the bargain and present you with a ropey-looking, but sturdy, boat and presents you with the choice of staying or leaving. After the cutscene ends, you'll be able to carry on with the rest of Far Cry 6's story… or hop in that boat and sail to America.
After this point, you can use any boat or air vehicle to travel towards the edge of the map—you'll know you're there as you'll see a "leaving Yara" message—and can access the secret ending. Keep going and the screen will eventually go dark before revealing Dani to be lying on a beach in Miami some three months later. The ongoing Covid pandemic gets a brief nod, as well as a message that Castillo has destroyed the Libertad movement and killed Clara. It's the 'best' ending for Dani as she gets to America, which was always her goal—becoming a guerrilla hero wasn't in her plans, after all.
When you load back, you'll be back at the start of the game but can fast travel to any locations you've discovered so far so you don't need to watch Castillo destroy the boat again.
Far Cry 6 post-credit scene
Finally, we come to the all-important post-credits scene. Juan meets an individual known as the Smuggler, who sounds an awful lot like Vaas from Far Cry 3. He's coming as part of Far Cry 6's season pass content which includes villains Pagan Min and Joseph Seed, too, though details of what it'll involve are thin on the ground.
A quick note: You'll need to finish Far Cry 6 properly to access the post-credits scene and you'll need to sit through the credits. Enjoy!