Retired Treasure Hunter's Memory

Hmm... Where is this place?
I think I've been there when I was younger.
Ah, that's right, this is the area near Ivero Cliff!
I was on the cliff when I saw something glistening in the water
and without thinking, I dived into the water below.
When I regained consciousness, I found myself at a shipwreck!
What did I find in the shipwreck, you ask? Hahaha, well that's my little secret.

Are you doubting me? I'm sure that map points to the area around Ivero Cliff.
Are you saying my memory can't be trusted?

It's my first time seeing such a shiny chest.
My poor heart might just burst!
I wonder if there are even more of these treasure chests somewhere out there...