The east coast of a country or region; often used with a country/region name (e.g. the U.S. East Coast).
アメリカ東海岸では夏にビーチが賑わう。
Beaches on the U.S. East Coast are busy in summer.
台風で東海岸の町が被害を受けた。
Towns on the east coast were damaged by the typhoon.
私は日本の東海岸をドライブしたことがある。
I have driven along Japan's east coast.