There is no Hoenn Underground only in Sinnoh. Sorry. =(
go underground and look for them
You can find them on Luvdisks in Pokemon Emrald and Ruby and Sapphire, and you find them underground in Pokemon diamond
You have to dive into the sea and go into a tunnel underground and you will find the waterfall there.
I'm not entirely sure but I have heard they are in the Underground. Go there to make your Pokemon happier.
Pokemon Ruby has Pokemon that Pokemon Sapphire does not and Pokemon Sapphire has Pokemon that Pokemon Ruby does not.
There is no Pokemon mansion in sapphire.
He is not in Pokemon: Sapphire. You will not be able to find him. He is in Pokemon: Diamond, Pokemon: Pearl, and Pokemon: Platinum. You will definitely have trouble finding him in Pokemon: Sapphire.
Evee is not availiable in Pokemon Sapphire.
Any Pokemon in sapphire but you have to migrate
sinnoh Pokemon won't appear in Sapphire version!
You cannot get Regigas in Pokemon Sapphire as it is from the next generation of Pokemon
All Pokemon in Pokemon sapphire can breed. Except for all legendaries.