coastal region; coastal area; coastline
Refers to the land area along the coast, often used in geographical, administrative, or disaster-preparedness contexts.
There are many fishing villages in the coastal area.
As the typhoon approached, an evacuation advisory was issued for the coastal region.
海岸 refers to the seashore or beach itself, whereas 沿岸部 denotes the broader coastal region, including inland areas near the coast.
Compound of 沿岸 (coast, shore) and 部 (part, section, area).