It will be a relatively small patch.
Image of a main character from the upcoming RPG Final Fantasy 16.

Square Enix initially said that there wouldn't be a day one patch for Final Fantasy 16. The studio may have been a tad hasty in making that proclamation because they are now saying that Final Fantasy 16 will indeed have a day one patch at release.

The good news here is that the patch will be quite small in size, roughly 300MB. During a pre-launch live stream for Final Fantasy 16, producer Naoki Yoshida confirmed that there will be a day one update for the game. Thanks to MP1st for picking up on this information from the live stream.

Yoshida notes that despite this update being available, it will not be required to play the game on release day.

What we just want everyone to know is that this update will come before the day one release. So if you have the digital version and you’ve already downloaded on the system and if your PS5 is hooked up to the internet, it will download this automatically, and it will be ready for day one so people will be ready to play as soon as the game unlocks. Also, this is a very, very minor issue, and so even if you don’t get the update, you will still be able to play the base game. This is a rapid patch, so it’s not necessary to actually play the game. So those of you who don’t have an internet connection, and maybe can’t get it in time, you will still be able to play the game
The changelog for the day one patch can be found below. In comparison to other day one patches for big-budget new releases, this is really just a small drop in the bucket. Too often we have seen day one patches for games that are several gigabytes in size and are required downloads before the game can even be played.

Final Fantasy 16 is slated to be out on June 22 for PlayStation 5.

Final Fantasy 16 Day One patch notes
  • Fix a control flag issue that can make progress impossible under very specific circumstances.
  • Fix an issue wherein the game close unexpectedly under very specific circumstances.
  • Optimize performance in several places
  • Fix some minor text errors​