When you go to sunyshore city to battle the last gym leader after you beat him you have to go get the move waterfall from jasmine who is the girl on the sand. Then you use surf on the water behind her which is route 233.
fish on route 223
Route 223 (Water Surface)
It is impossible to capture a Mantine in Pokemon Platinum. However you can capture a Mantyke, its pre-evolution, on route 223 by surfing and then evolving it by leveling it up with a Remoraid in your party. There is a 10% chance of encountering a Mantyke on route 223.
You can go fish at route 223 and route 230 with a super rod and eventually you'll find one
There are two swimmers ready for a double battle in route 223 , battle them and one will have an octillery . ;):)
route 223 or route 230
fish on route 223
Route 223 (Water Surface)
North of Sunyshore City. It leads you to the Pokemon League.
route 223 - 230 super rod
It is impossible to capture a Mantine in Pokemon Platinum. However you can capture a Mantyke, its pre-evolution, on route 223 by surfing and then evolving it by leveling it up with a Remoraid in your party. There is a 10% chance of encountering a Mantyke on route 223.
route 223 and in the huge field past valor lakefront
A trainer on route 223 outside of sunyshore city on your way to the Pokemon league.
You can go fish at route 223 and route 230 with a super rod and eventually you'll find one
If your talking about octillery go to route 223 or whatever and use super rod
on route 223
you have to surf for it