in one of the caves if you want futher info go on utube and the Pokemon masters like me will help you
Fridays at whirl islands
You find it in Union Cave on Fridays only
Chat with our AI personalities
you can find them on fridays in unoin cave
you need a cheat that can catch a trainer's Pokemon to have lapras. because there is a trainer that has a lapras.
you find lapras in union cave B2 only on fridays
Union Cave
You can find it in water in the Safari Zone. It's on the Rocky Beach Area.