1. Waters under the sovereignty and jurisdiction of a nation, typically extending from the coastline to the territorial sea limit (usually 12 nautical miles)
The country enforces fishing regulations in its national waters.
O país aplica regulamentações de pesca nas suas águas nacionais.
2. All bodies of water (rivers, lakes, coastal areas) that belong to and are controlled by a sovereign state
Environmental protection in national waters is a priority for the government.
A proteção ambiental nas águas nacionais é uma prioridade do governo.