How do you catch Suicune on emerald?

You can't catch Suicune in Pokemon Emerald. Suicune, alongside Entei and Raikou, are Legendary Pokemon introduced in Pokemon Gold and Silver. They are not available in Emerald.

However, you can find them in other Pokemon games, such as:

* Pokemon Gold and Silver: You can find them by traveling around the region and encountering their random appearances.

* Pokemon Crystal: You can find them by traveling around the region and encountering their random appearances.

* Pokemon Ruby and Sapphire: They are obtainable through the "Secret Base" system, where players can encounter them in specific locations.

* Pokemon Omega Ruby and Alpha Sapphire: They can be found by traveling around the region and encountering their random appearances.

Remember that catching Legendary Pokemon can be challenging, so be sure to prepare beforehand with strong Pokemon and plenty of Poke Balls.