completely by chance
route 223 or route 230
You can capture a wailord in route 230. If you can not find it you better capture a wailmer and evolve it.
You can go fish at route 223 and route 230 with a super rod and eventually you'll find one
you can get a wailord at route 223 or 230 using a super rod. (very uncommon)
It is not an HM anymore, you can get a wailord with it on route 230 super rod
You can catch level 40-55 Wailords with the super rod at Route 223 and Route 230, but the chance of a landing Wailord on your super rod is very rare, at 5%. Level 30-40 Wailmers are much more common, at 30%. To save time, catch a Wailmer with a super rod and train it to level 40 and it will evolve into a Wailord.
no it goes up to 230
by surfing you can get sealio,pelipper and tenticruel and by fishing with the old rod you can get magikarp, good rod u can get, magikarp and remoraid and with the super rod you can get gyarados, wailmer, octillery and wailord
at route 230 while you are surfing
beat the elite four then follow route 230 and route 225
route 223 - 230 super rod
you can get corsola only in route 230 BUT dawn's sister has to tell you if it's there