I've heard many things about Koh Tao diving and, in my eyes,
most are lies.
Despite what it may once have been, the island is overrun by
tourists; and the sea, by tour groups of SCUBA divers.
Moreover, the shallows are so overwhelmed by boat traffic as to
make it entirely a swim between the lines operation.
Go elsewhere if you'd like to free-dive or SCUBA with anything
less than a full house.
(And this was off-season!)
Despite all that, and despite the water made murky by so much boat
traffic (and seasonal rains!), we enjoyed ourselves as best we could.
Right upon entering the water, we spotted a beautiful wart slug (Phyllidia varicosa).
Then not far along from there, a sawtooth
The cube-looking structures are part of an artificial
Which, in my sad opinion, is doomed to fail unless the island
can restrict the number of tourists.