Which pokemon can learn Dive?

On wiki is wrote that the pokemons vaporeon, saidine, selkid... can learn dive.
But in the game they can't. Is that a bug or something else?
Thanking you for responding

Dive is needed to get to the 8th gym and, since the 8th gym isn't implemented yet, neither is Dive.

How can train my pokemons against strong pokemons?

There are some trainers throughout the game who you can rebattle now. Their pokemon's levels dynamically change to match yours so you get good xp whenever you fight them.