i think mossdep, but i play emerald
simply press 'B' or go to pokémon list > *pokemon with 'dive' > DIVE
You can't unless you trade a Pokemon from Pokemon Ruby, Sapphire or Emerald and get a Pokemon that knows Dive. The HM Dive is not necessary in Pokemon Firered and is thus not avaliable. However, a Pokemon that knows Dive can be traded from Pokemon Sapphire, Ruby or Emerald version to Firered.can notI can't remember much, but I think you have to get it from Wallace or Juan.
You go to Steven's house in Mossdeep City
use dive go in the deep sea grass he will be in the grass
You have to dive into the sea and go into a tunnel underground and you will find the waterfall there.
At the start of the game, there is a choice between three Pokemon to choose. Mudkip can learn dive as he is a water/mud Pokemon. Another Pokemon that can learn dive is kyogre, which is at the end of the game. Any water Pokemon should be able to learn dive, surf and waterfall though.
The is a huge white rock, with dive spots round it, dive there, and you find an underwater cave. Go in and surface again and You find Sootopolis
Steaven gives it to you at mossdeep city, go to his house after you beat the gym and he will give it to you.
You have to teach a water type Pokemon dive. You receive the HM "dive" in Mossdeep City after you defeat Magmas at the Mossdeep Space Centre. You have to go to Steven's house, I believe.
you first go to steven to get dive and dive dvie
Easy you go see steven to get the HM Dive then use it to go to Sootopolis City where your last gym is.
Dive is not an HM in firered but if you trade a Pokemon that can learn dive to ruby, sapphire or emerald then teach it dive then trade it back it will still have dive however you cannot use it outside of battle.