They can be found in the dark cave but they are rare.
some times you can catch Dunsparces there
Wobbuffet can be found at Dark Cave, which is at the entrance of Route 45.
You can get Horsea in Dark Cave or Whirl Islands. You'll need to Surf on water to get it.
You have to go to the top of Bellsprout Tower and defeat the elder, in which you will get the item Flash. This move allows you to light up any dark cave.
in dark cave
In Dark Cave.
They can be found in the dark cave but they are rare.
You can find it in the Dark Cave.
A Dark Ball could work nicely here, since you're in a cave.
No. But they have dusk balls which helps you to catch Pokemon in night or in a cave.
some times you can catch Dunsparces there
Route 31, outside of violet city.
In Gold and Silver Wobbuffet can be found in Dark Cave. In Crystal, in addition to Dark Cave, you can also get one at the Goldenrod Game Corner for 1500 coins.
It depends in your playing soul silver or heart gold you catch in one of the dark caves in the water.
Catch it as you would a normal Pokemon, they just have a lower Catch Rate. If the legendary Pokemon is in a cave or dark area, use Dusk Balls and so forth.
Wobbuffet can be found at Dark Cave, which is at the entrance of Route 45.