Any Pokemon in Pokemon Red, Pokemon Blue or Pokemon Yellow will only be transferable to Pokemon Sun & Pokemon Moon.
Since the Pokemon Direct this morning, many have been speculating if you will be able to transfer Pokemon from Pokemon Red Pokemon Blue or Pokemon Yellow to other Pokemon games such as Pokemon X, Pokemon Y, Pokemon Omega Ruby or Pokemon Alpha Sapphire. The statement from the official Pokemon Bank website is as follows:
“Note that Pokémon cannot be moved directly from Pokémon Red, Pokémon Blue, and Pokémon Yellow to Pokémon Omega Ruby, Pokémon Alpha Sapphire, Pokémon X, or Pokémon Y via Pokémon Bank.”
While unfortunate, it is nice to have the ability to move from the classic releases to the recently announced Pokemon Sun and Pokemon Moon.