It is found northeast of One Island, in the cave where the hot springs are. Talk to one of the old men to get the HM.
No its not an HM in leafgreen.
The HM's that are in leafgreen are: Cut, Fly, Surf, Strength, Flash, Rock Smash, Waterfall.
There's no Dive HM on Pokemon Leaf Green.
On route 16.
you cant
In icefall cave.
You cannot get HM Dive in Pokémon LeafGreen.Since Dive is not an HM in leafgreen the only way to get one of your Pokemon to learn Dive is to trade it to ruby, sapphire or emerald then teach it Dive using the HM then trade it back to leafgreen.
Icefall cave.
There isn't one
HM03 is surf
you get it in the captains quarters.
HM, Waterfall is in the Ice Cave on Four Island.