You can catch it at the Pastoria Great Marsh.
In the great marsh
You can find it from Great Marsh.
you have to evolve it from scorupi which you get at the great marsh You can also catch it in the great marsh but its only a 10% encounter, i suggest using the binoculars
For a Pokéner to catch a Marill to evolve into an Azumarill,search in either the Safari Zone or Mt. Mortar. The Safari Zone is easier. Marill appear at night in a certain area.
Marill can be found in Pokemon Peal in the Great Marsh area. The Great Marsh let players catch Pokemon not found anywhere else in the region.
in the great marsh but its weak better catch a buizel
evolve a marril --EDIT: September 1, 2010-- Evolving a Marill would result in an Azumarill, NOT an Azurill. To get an Azurill, you need to give a Marill/Azumarill a SEA INCENSE from the top of Mt. Pyre, and put it in the Daycare with an Azumarill/Marill of the opposite sex or a Ditto.
You can catch it at the Pastoria Great Marsh.
In Platinum, you can find it in the Great Marsh.
In the great marsh
you go into the great marsh
After you get the national dex he "might" appear in the great marsh(but he's very rare)
Well, In the Great Marsh. Roselia
You can find them in the great marsh area 3
You can find it from Great Marsh.
at the great marsh in pastoria city