Without being a party to UNCLOS, U.S. underseas cables only protected by 1884 telegraph treaty

At present for the United States, the operative international treaty for international cables is the 1884 International Convention for Protection of Submarine Cables. This venerable treaty was designed for old international telegraph cables. While most of its features are included in UNCLOS, UNCLOS provides real improvements required by the steady progress made in international communications in the past 122 years since the 1884 treaty entered into force. UNLCOS is essential for modern telecom business.

For example, under the 1884 treaty, nations are required to provide criminal and civil sanctions for negligent or intentional actions which cause injury to a submarine telegraph cable. Unfortunately, under this treaty, the cable owner must wait until the damage is done before sanctions are triggered. Under UNCLOS, conduct which is likely to result in injury can also be sanctioned. Under UNCLOS, a cable owner has a remedy to prevent the injury to critical infrastructure in the first place. When one considers the average $1M plus cost of a cable repair and the potential disruption a cable break can cause to vital economic and strategic interests, it is easy to see why cable owners want UNCLOS now.

The 1884 treaty is limited to telegraph cables. UNCLOS provides and expands the protections accorded telegraph cables to all international cables regardless of use.