The area where the sea meets the land; the shore, coast, or beach (the part of land by the sea).
夏休みに家族と海岸へピクニックに行った。
I went on a picnic to the coast with my family during summer vacation.
海岸沿いを散歩すると、潮の香りが気持ちいい。
Walking along the coast, the smell of the sea feels pleasant.
台風で海岸の遊歩道が壊れてしまった。
The promenade on the coast was damaged by the typhoon.