To find this waypoint you will have to go to the west of the Yazadaha pool in Sumeru. At the location of the waypoint you can find a waterfall and just behind it will be the Teleport Waypoint. But now you will have to unlock it.
To unlock it you will have to solve several puzzles that at the same time unlock the Fragment of Childhood domain. After this you will have to teleport to the Statue of the Seven, west of Yazadaha Pool, and then go west, where the waterfall is.
You will have to slide down to notice that the water is gone. So interact with the landmark in question and you'll be able to unlock it, as well as the Fragment of Childhood domain.
Now that we have finished this guide on how to unlock an underwater waypoint in Genshin Impact, we hope that we have been very helpful and we hope that you will be able to access this waypoint quickly.