Dive is not an HM/TM anymore so it can't learn dive, but you can get it from a different region so if you trade a Pokemon holding that move then take it off them it can learn dive.
Wailmer EDIT: I think Wailmer can only learn dive.
Dewgong learns Dive at level 45.
It can't learn it whatsoever
you can learn HMs at any level, but only if you have a compatible pokemon.
Wailord learns Dive at Level 46 in Pokémon Diamond.Over nine thousand
Dive is not an HM move in Pokemon Platinum. There are, however, Pokemon that can learn it by level up.
No. Dive is an HM in kanto, so you can't use it out of battle. Some Pokemon can learn dive with no Tms or HMs, but you can't use it as a field move.
Gyarados cannot learn Dive by itself from leveling and must learn it from the HM Dive which is not available in Pokemon Platinum. The HM for Dive is only available in Pokemon versions; Ruby, Sapphire, Emerald, White, Black, White2, and Black2
You, unfortunately, cannot dive on diamond, pearl, or platinum. Sorry.
The HM dive cannot be acquired in Pokemon diamond.
You can't because you can't dive in Pokemon diamond or pearl.
There is no HM called dive in Pokemon Diamond you fat oaf.