How do you get shamin in pokemon platnuim?

You can get Shaymin in Pokémon Platinum by using an event item called the Oak's Letter. To obtain the Oak's Letter, you need to have a copy of Pokémon Diamond or Pearl and have completed the Sinnoh Pokédex. Once you have completed the Sinnoh Pokédex, go to Floaroma Town and speak to Professor Oak in his laboratory. He will give you the Oak's Letter.

With the Oak's Letter in your possession, go to Route 224. There is a small alcove on the west side of the route, near the entrance to the Lost Tower. There is also a flower garden to the west of this alcove. Enter the flower garden and interact with Shaymin to start a battle with it.

You can only obtain one Shaymin per game. Once you have obtained Shaymin, it will be registered to your Sinnoh Pokédex and you can find it in your PC.

Here are some additional tips for catching Shaymin:

* Make sure your Pokémon are at a high enough level. Shaymin is a level 30 Pokémon, so you will need to have some strong Pokémon in order to defeat it.

* Use Pokémon with moves that are effective against Grass-type Pokémon. Some good choices include Fire-type, Ice-type, Flying-type, Bug-type, and Poison-type moves.

* Use status effects to your advantage. Paralyzing or poisoning Shaymin can make it easier to defeat.

* Be patient. Shaymin can be a difficult Pokémon to catch, so don't get discouraged if you don't catch it the first time.