Nope, you have to fish.
I'm sorry, but you will have to trade from Pokemon LeafGreen or FireRed. There is no way to find a Poliwag in the wild in Emerald.
in the grass, water or buildings =.=''
You find pokemon by walking in tall grass.
Find it on a route in the grass then use the masterball.
u can find it in the grass of seven island .It is in seuvault canyon
You can't catch a poliwag in Pokemon Sapphire. You have to trade from Pokemon Fire Red or Pokemon Leaf Green.
You find it in the grass patch left of the city that mistys gym is in
You find it in the grass in sevault canyon on seven island.
You can find one in the grass on the Route east of Celadon City.
Chose Squirtle as your starter, get the national dex, then you will find it in random grass.
You catch him at the Pokemon MansionNo, it is found in the patches of grass on Mt. Ember.You can find it in the Pokemon Mansion which is located on Cinnabar Islands.
You'll need to trade for it.