I took this photo when I was in Bandra, Mumbai during Nov 2016 and observed that it has written like "Bandra History 1774 British Soldiers Pond". So, as per the history, those British Soldiers would have enjoyed this pond (Bandra sea) at that time for relaxing, fun and swimming all around, and it is still filled up rock and water log here and there naturally which Indians and Foreigners now enjoying it.
The water-log or water from beaches as a tide increases and filled up over there. They are depend on daily timing and monsoon. The one who enters there must be very careful as the rock and little water log here and there is slippery.
This location is just near the Bollywood star Shah Rukh Khan's home. You may visit British Soldiers Pond to know more detail about Bandra History 1774.