Route 20

16 Pokémon can be caught at Route 20 in Kanto — highlighted on the map below.

Route 20 is a body of water spanning southern Kanto from Route 19 east of it to Cinnabar Island in the west, with the Seafoam Islands rising at its midpoint. A labyrinth of rocks around the islands cuts the route in two, and crossing normally requires passing through the underground caves beneath Seafoam, entered from the northern cave on the east or the southern cave on the west. A small rest platform west of the islands breaks up the long swim toward Cinnabar.