Treasure Hunter Achievement in Octopath Traveler

Warning: There is ONE missable chest in the game tied to this achievement. Make sure to get the chest during Cyrus Chapter 3. I would also highly, highly suggest you use the Excel sheet I linked in the Road Map directly from the start of the game. There is no way to track your progress for this in-game.

To unlock this achievement, you will need to collect every treasure chest in the game, including all the locked purple chests that Therion can access. You may come across some of these before you recruit him, so be sure to come back when necessary. After defeating Galdera, you will acquire the Spurning Ribbon, an accessory that wards off all random encounters. If you need to find any missing chests at this point, be sure to equip that so you can simply run around freely. Even though I followed the walkthrough and excel sheet, I still somehow missed three chests that I needed to search for manually which took multiple hours, so be thorough from the start!