You have to delete dive before you transfer it to platinum.
You'll have to migrate wailmer into soulsilver by using either ruby, sapphire, or emerald pokemon games. Step 1: Insert both soulsilver and your third gen pokemon games into a ds. Step 2: Start up soulsilver and choose the migrate pokemon from the opening screen. Step 3: Choose wailmer and 5 other pokemon to migrate. Step 4: Go to the pal park to receive your wailmer. (You'll need to have the national pokedex for this)It is Impossible to get walimer without the global trade center
Wailmer evolves at Level 40.
Wailmer evolves into Wailord starting at level 40.
My wailmer evolved earlier today at level 40.
By fishing for a wailmer in the ponds in route 123.
I am looking to join Wailmer to my team.But, no you can't catch it with an old rod
get it to level 40
fish on route 223
You can't catch a Wailmer in HeartGold but you can trade with someone to get it. Or you can do what I did and migrate it from another game. But be careful, if you migrate a Pokemon from another game you can't send it back to where it came from.
wailmer evolves at level 40 on Pokemon sappphire.Hope I helped
Train wailmer to level 40.
Go to the Flower Shop on Route 104