Swarms are another feature that have been retained in the change from Diamond & Pearl to Platinum. Swarms remain the same and require you to have the National Pokédex. Once you do, go see your rival's sister in Sandgem Town. She will tell you where the swarm is and what Pokémon is there. Once known, you can go there and find out. The swarms change every day so always check so that you can get the Pokémon you want

Swarming Pokémon

Location Nat No. Pic Name Type 1 Type 2
Route 201 #084 Doduo
Route 202 #263 Zigzagoon  
Route 203 #104 Cubone  
Route 206 #246 Larvitar
Route 207 #231 Phanpy  
Route 208 #206 Dunsparce  
Route 209 #209 Snubbull  
Route 214 #325 Spoink  
Route 215 #096 Drowzee  
Route 217 #225 Delibird
Route 218 #100 Voltorb  
Route 221 #083 Farfetch'd
Route 222 #300 Skitty  
Route 224 #177 Natu
Route 225 #296 Makuhita  
Route 226 #098 Krabby  
Route 227 #327 Spinda  
Route 228 #374 Beldum
Route 229 #127 Pinsir
Route 230 #222 Corsola
Valley Windworks #309 Electrike  
Eterna Forest #287 Slakoth