Well,if you havn't gone to Team Magmas hideout to the right of Lilycove,go there,then go to Slateport where you find Capt.Stern then Maxie uses the Megaphone then they steal the submarine, then go to route 118, teach one of your pokemon Dive, then go to the dark patches of the sea, use Dive, then swim around and you should find a cavern and go through there, if you have gone to Team Magmas hideout and Slateport, just teach one of your pokemon Dive, go to route 118, Dive, swim around and find the cavern.
(by the way, I know its T.M.I. ((to much information)) but I really wnat to help)
the hm dive is not available in pearl.
Dive is an HM, but in Diamond,Pearl, and Platnum, it is a TM
You must beat the MossDeep City gym to use the HM for Dive.
The HM dive cannot be acquired in Pokemon diamond.
The short answer is no. There is no Dive, HM 08, in Pokemon FireRed.
The HM containing Dive is given to you by Steven Stone in Mossdeep City. Be aware that the gym leaders Liza and Tate must have been defeated before the HM can be received.
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.
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
If you lose an HM, you can get it again where you got it the first time.
There's no Dive HM on Pokemon Leaf Green.
Go to Steven's house in Mossdeep city. Talk to him. He'll give you HM Dive.
The HM Dive is not in SoulSilver or HeartGold, for there is no deep water to dive into.