You unlock the loading screen of open waters after completing 8 of the challenges. When you have completed 8 challenges, you will also get the challenge to find this hidden letter. You will find the hidden “O” in Graggy Cliffs, next to the house which can be found right by the sea.
Hidden O found in the Open Water Loading Screen Location
Fortnite Chapter 2 has unlocked a completely new map, giving it new places and challenges. One of today’s challenges requires the following from you:
Search hidden ‘O’ found in the Open Water Loading Screen – Fortnite Chapter 2 Open Water
This challenge counts towards the “Alter Ego” challenge “Collect F-O-R-T-N-I-T-E Letters Hidden in Loading Screens” which unlocks the mystery skin for this season when you collect them all.