any sea
Wailord is an immense Water type Pokemon. It can be encountered in the wild in Pokemon Sapphire while Surfing on Route 129.
wailord you have to evole from wailmer and relican you find in dive mode.
sea of wailord
in shinetown city
route 129
you can find it at rout 129
You cannot catch Wailord. You can, however, catch Wailmer, which evolve into Wailord starting at level 40.
find a wailmer then evolve it
You can find it in Route 129 but it is rare.
Wailord is not a legendary pokemon. Legendary pokemon are pokemon that typically play some role in the story, and can not evolve from anything or into anything. They also can not be hatched from eggs. Wailord plays no major role (if any) in the main stream pokemon games, and it evoles from Wailmer. Therefore, wailord is unable to be classified as a legendary pokemon. While wailord can be difficult to find in some generations and is often considered powerful and cool, it is not a legendary pokemon. I wrote this answer to help explain to my cousin that wailord is not a legendary even when he insists that it is for various reasons. I hope this was helpful and help led you understand legendary pokemon as a whole.
wailord is in undella bay
it evolves from a wailmer where you can get it basically in any ocean