Treasure BeachFireRed&LeafGreen
"A small beach on the southeast shore of One Island. Items wash up on the sand, making it worth a quick stop while exploring the Sevii Islands."
TREASURE BEACH MAP
Sandy beach wrapping around the south shore of One Island. Surf south from the main town to land here. The path follows the shoreline end to end.
Pokemon Encounters
Tangela at 30% is the draw, a Grass-type that's hard to find outside Route 21. Persian at 5% and Meowth at 10% roam the beach grass. Levels run from the low 30s to 40.
Old Rod1
Good Rod3
Super Rod7
Magikarp
Also found in 41 other locations
ITEMS
Every pickup here is hidden: Star Piece, Big Pearl, Pearl, Stardust, and an Ultra Ball. Pure Itemfinder territory, and everything sells for good money at the mart.
Big Pearl
A quite-large pearl that sparkles in a pretty silver color. It can be sold at a high price.
Big Pearl
A quite-large pearl that sparkles in a pretty silver color. It can be sold at a high price.
Pearl
A relatively small pearl that sparkles in a pretty silver color. It can be sold cheaply.
Star Piece
A shard of a pretty gem that sparkles in a red color. It can be sold at a high price.
Stardust
A pretty red sand with a loose, silky feel. It can be sold at a high price.
Ultra Ball
A very high-grade BALL that offers a higher Pokemon catch rate than a GREAT BALL.
TRAINERS
A lone Swimmer with Water-types on the beach. Barely a speed bump.
Amara
Treasure Beach Guide
Islands One through Three unlock after you beat Blaine on Cinnabar Island. Bill takes you there as part of the story. Islands Four through Seven require beating the Elite Four first, then completing Celio's Ruby and Sapphire quest on One Island to get the Rainbow Pass.
You can physically reach all seven islands without it, but evolved Johto Pokemon only show up in the wild after you get the National Dex. That means 60 or more Pokedex entries plus completing Celio's quest. If you're only seeing Kanto species, that's why.
Old Rod only catches Magikarp. Good Rod adds Horsea, Poliwag, and Goldeen depending on the area. Super Rod is where the good stuff lives: Gyarados, Seadra, Staryu, Kingler. You get the Old Rod in Vermilion, Good Rod from the Fishing Guru south of Lavender Town, and Super Rod from his brother on Route 12.
If the encounter table shows Surfing or any Rod encounters, yes. Surf itself is HM03, found in the Secret House deep inside the Safari Zone. You also need the Soul Badge from Koga in Fuchsia City to use it outside battle.