Final Fantasy 16: The Rising Tide - the game's second DLC - takes place before the ending of the main game. Square Enix has revealed that fans will be able to play the DLC from April 18, bought on its own or as part of the existing Expansion Pass. Either way, you'll need to also own the original game.
"An unmarked letter arrives at the hideaway containing a most curious request: the Dominant of Leviathan, the long-lost Eikon of Water, needs rescue," Square Enix says. "To heed this call, Clive and his companions must journey to Mysidia - a hidden land under a blue sky - where they will uncover the tragic history of a forgotten people."