You have to choose the water pokemon as your starter. Or trade it from a friend or another console of yours.
in squirtle land
Get it for your starter Pokemon
They are bulbasaur, charmander, and squirtle.
firered and leafgreen version
it is bulbasaur ,squirtle, and charmender
squirtle charmander and bulbasaur
To get Pokemon 7 you have to choose squirtle as your starter Pokemon.
you can't, you need to trade with a game that you can start with a squirtle (ie. Pokemon leafgreen, Pokemon firered)
You cant catch a squirtle in Pokemon firered nor in Pokemon leafgreen. Squirtle is a starter Pokemon so you cant find or catch one unless you use a game shark.EDIT by Man spider27: Although it is- as far as I know- impossible to capture Squirtle or Bulbasaur in Pokemon leafgreen it is possible to find Charmander in the Old Mansion on Cinnabar island. Hope I helped!
you have to migrate from leafgreen/firered from squirtle
Trade them from firered or leafgreen.
They are not catchable on any Pokemon game,however you can trade to get the starter Pokemon squirtle and charmander on Pokemon Leafgreen/Firered.