How do you get the premier ball in leafgreen?

You can't get the Premier Ball in Pokemon LeafGreen. It was introduced in later generations of Pokemon games.

LeafGreen features the following Poke Balls:

* Poke Ball: The basic and most common Poke Ball.

* Great Ball: A slightly more powerful Poke Ball with a higher capture rate.

* Ultra Ball: A very powerful Poke Ball with a much higher capture rate.

* Master Ball: The most powerful Poke Ball, guaranteed to catch any Pokemon.

* Safari Ball: A special Poke Ball used only in the Safari Zone.

If you're looking for a similar ball, the Ultra Ball is the closest equivalent to the Premier Ball in terms of effectiveness.