Maritime Zones: Internal Waters

Internal waters are generally defined in relation to the territorial sea as the waters inside the inner limit of the territorial sea.

But internal waters can exist without a territorial sea, and a territorial sea can exist without internal waters. So, internal waters include littoral areas such as ports, rivers, channels, bays, lakes, and other marine spaces landward of the baseline.

Speaking about the limits of the territorial sea, as claims handlers, what might be interesting to know about internal waters?

?States have the same sovereign jurisdiction over these waters as they do over other territory. The subsoil and the aerial space below and above those areas belong to it.

? The normal baseline for measuring the breadth of the territorial sea is the low-water line along the coast as marked on large-scale charts officially recognized by the Coastal State. [UNCLOS Article 5 ].

Importance of baselines:
✅Fundamental to maritime claims
✅Define outer limits of internal waters
✅Starting point for claiming maritime zones
✅Provide basepoints for generation of limits of national maritime claims and maritime boundary negotiations

? Ships entering internal waters must conform with the rules and regulations of the Coastal or Port State (Port State Control). The Coastal State may exclude foreign flag vessels from its internal waters subject to the right of entry of vessels in distress. The right of innocent passage does not apply in internal waters. The entrance for purposes of commerce, navigation or even fisheries is subject to bilateral agreement with the Coastal State.

? For the purpose of delimiting the territorial sea, and in accordance with the Convention, ” the outermost permanent harbour works which form an integral part of the harbour system are regarded as forming part of the coast” (UNCLOS Article 11), which allows them to be used as support points for the effects of drawing the baselines straight.

? Important areas of internal waters such as navigable rivers have often, however, been subjected to special regimes, eg the international rivers regime as well as the Kiel Canal, the Suez Canal and the Panama Canal.

? All “archipelagic waters” within the outermost islands of an archipelagic state such as Indonesia or the Philippines are also considered internal waters, and are treated the same with the exception that innocent passage through them must be allowed. However, archipelagic states may limit innocent passage to designated sea lanes within these waters.