You buy one
u can't buy one!
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.
There is not a diving mask. The closest I can think of is a Dive Ball. If you want to get Pokemon from underwater, use a super rod.
In Platinum, Diamond, and Pearl they removed Dive.
Dive is an HM, but in Diamond,Pearl, and Platnum, it is a TM
on your way to victory road, in the water you will see a poke ball that is a dive ball
Wailmer EDIT: I think Wailmer can only learn dive.
on Pokemon dimond there isn't a move caled dive. but there are a hm called surf and waterfall.you cant
Dive is absent in Pokemon pearl,diamond,platinum,heartgold,and soulsilver . But will return in Black/White =-)
You can't.
There is no HM for Dive in SoulSilver, but you can get it by transferring a Pokemon who knows dive into SoulSilver the Pal Park. but you can get dive as a HM in Pokemon black and white but not in soulsilver,heartgold,platinum,diamond,and pearl