Use a super rod on the beach in Slateport city
You use the Super Rod at Lilycove, there's loads of Wailmer, but be patient, a staryu will soon show up ( Are you refering to Sapphire or Emarald?)
a wingull that you can find in pokemon emarald
Super rod all over the place until you find a wailmer
No, Wailmer can only be found on water routes by fishing or surfing.
You have to find it in the cave
Dewford cave, second floor or lower.
psypoke.com
get a wailmer level 40
the easiest place to catch it is on mossdeep city and use a super rod in the water, you will ALWAYS find a wailmer this way
find a wailmer then evolve it
just go to mauville city and you'll find the gym
Go to the Fight area and run right. you will arrive at a shore, fish there with a super rod and u wil find a wailmer sooner or later