Action replay
In DP, it would be the Turnback Cave in the Spring Path after you beat the elite 4. In Platinum, it would be in the Distortion World (It like a giant puzzle).
there is no sunny shore city on emerald
to get to sunny shore in Pokemon diamond you need to catch dialga at spear pillar
Sunny Shore City is a location in the games Pokemon Diamond Pearl and Platinum. The city is powered by solar energy.
The seal shop in dimand, pearl, and platinum is in sunny shore nere the poke'mart. I hope this helps
Volkner
misty
you have to get dialga / palkia
HM Waterfall
sunny
you have to get to the top of mount coronet and catch giratina in the reverse world then go to sunny shore city
Cool air from the shore will travel to the sea.