The land along the sea or a large body of water — the coast or shoreline.
天気がいいので沿岸を散歩した。
Because the weather was nice, I walked along the coast.
台風で沿岸地域に大きな被害が出た。
The typhoon caused major damage to coastal areas.
沿岸の道路は潮風の影響で塩害が進んでいる。
The coastal road is being affected by salt damage from the sea breeze.
Coastal waters or the coastal zone — the sea areas near the shore and the region where coastal activities occur.
沿岸漁業はその地域の重要な産業だ。
Inshore fishing is an important industry in that region.
沿岸警備隊が不審な船を監視している。
The coast guard is monitoring a suspicious vessel.
沿岸海域ではマングローブが重要な生態系を支えている。
Mangroves support an important ecosystem in coastal waters.