Appendix:Diamond and Pearl walkthrough/Section 13
Now that you can use Surf......
There are a lot of places you can access with the move Surf, such as Routes 218, 219 to 221 and Fuego Ironworks. These mentioned places will be further introduced.
Some places that you accessed before may contain some items that you couldn't reach. With Surf, you can get those items.
Oreburgh Gate
Route 204
Ravaged Path
Valley Windworks
Route 211
Route 208
Route 209
Route 210
Route 214
Route 213
Hotel Grand Lake
Pastoria City
Route 212
Fuego Ironworks
Go to Route 205. Remember the house south of Eterna Forest, which you can take a rest and heal your Pokemon? Head south from there and get down the stairs. Turn west when you can. You will see a river. Now that you can use Surf, you can get through this river. This will bring you to Fuego Ironworks.
Floaroma Meadow (Northern part)
Return to Fuego Ironworks again, but get to the south of the river. Through the entrance, you will be in another part of Floaroma Meadow. You can get many items here. Most of them are hidden, so use your Poketch App Dowsing Machine to help you.
Sandgem Beach and Route 219
Head south from Sandgem Town. There is a Potion on Sandgem Beach, but you should probably had taken it at the start of the game. Head south, use Surf, and you'll be on Route 219.