Train wailmer to level 40.
in magma hideout
They are rare if you surf on Route 129. It's much easier to catch a Wailmer and evolve it into Wailord.
There's only a small area to find Wailord off of Ever Grande City in Sapphire. An easier way to catch one is to get a Wailmer in the high 30's. Then just get him to level 40, where he will evolve to Wailord.
you cant catch one wild you have to evolve wailmer at lv 40
Wailord is an immense Water type Pokemon. It can be encountered in the wild in Pokemon Sapphire while Surfing on Route 129.
route 129
Wailord's pretty rare,but surf between mossdeep and Pacifidlog untill you found it.
Wailmer can be found in Mossdeep City near the palm trees. Wailmer is a water type Pokemon that later evolves into Wailord.
By catching a Wailmer, train it up to level 40, an it will evolve. In sapphire i think you can catch a wailord.
You cannot catch a Wailord but you can, however, evolve a Walmer at level 45.
You do not need a Wailord to catch a Registeel in Pokemon Emerald. You may need a Wailord or any other water-type Pokemon to surf to the place where you catch Registeel, but other than that, you don't need a Wailord.
Get a Wailmer and evolve it. It evolves into Wailord at level 45.