use the super rod on the beach at lilycove city.
The Pokemon Wailmer evolves into Wailord at level 40 on Pokemon Black.
I am looking to join Wailmer to my team.But, no you can't catch it with an old rod
Yes, you can. Though it's much easier and faster to catch a Wailmer by fishing.
It evolves at level 40.
undella bay
Ruby or Saphire
You catch it in the seaweed next to sootopolis city
wailmer and sharpedo
Catch a wailmer and get it to level 40.
TRADE IT FROM RUBY OR SAPHIRE.
Saphire Version
catch a wailmer with a super rod then level it to 40