There is a specific place where somehow let you see underwater.
MC-158187
Can see through solid blocks via underwaterwater.
Resolved
Duplicate
0
Yu Katsuragi
(Unassigned)
Unconfirmed
World generation
1.14.4
Retrieved
Thank you for your report!
We're actually already tracking this issue in MC-63020, so I resolved and linked this ticket as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
If you haven't already, you might like to make use of the search feature to see if the issue has already been mentioned.