In Undella City, there is a girl off to the left of the Pokemon center in a white dress. Talk to her, and she will give you the HM Dive. You can then teach it to a Pokemon and enter the Abyssal Ruins.
the dive hm. the lday in undella town gives it to you.
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
Dive is absent in Pokemon pearl,diamond,platinum,heartgold,and soulsilver . But will return in Black/White =-)
The only thing you can dive for is the abyssal ruins.
Undella Bay
In Undella Town
at Undella town a girl will give it to you
dive is given to you by a girl in front of a house in undella town
You get Dive in Undella town. The lady that gives it to you is the only women outside.
There's a lady in Undella Town you can talk to to get Dive. She's in front of the first house.
After you defeat N and Ghetsis, go to Undella Town and a girl will give you the HM Dive.
dive underwater