territorial waters; territorial sea
Refers to the belt of coastal waters extending at most 12 nautical miles from the baseline of a coastal state, over which the state has sovereignty.
その船は日本の領海を侵犯した。
The ship violated Japan's territorial waters.
領海の幅は通常12海里とされている。
The breadth of the territorial sea is generally set at 12 nautical miles.
A foreign fishing boat violated Japan's territorial waters.
The vessel was operating within the territorial waters.
領空 refers to the sovereign airspace above a country's land and waters, while 領海 refers to the sovereign sea area itself, and learners often confuse the two similar-sounding legal terms.