January 26, 2026
What Is AMTS? The Automated Maritime Telecommunications System Explained
AMTS is a specialized FCC-licensed maritime radio service for data and voice communication along US inland and coastal waterways. Here's how it works.
The Automated Maritime Telecommunications System (AMTS) is a specialized radio service established by the FCC for voice and data communications along US coastlines, rivers, and inland waterways. It operates in the VHF band and serves commercial maritime users who need reliable communications for vessel tracking, fleet management, and operational coordination.
What AMTS Does
AMTS provides radio-based communications infrastructure for maritime users, functioning somewhat like a cellular network for waterways. AMTS base stations are located along coastlines and major inland waterways, providing coverage to vessels in their service areas. Services provided over AMTS include:
- Voice communications between vessels and shore
- Data communications for vessel tracking and fleet management
- Integration with broader telecommunications networks
- Automatic identification and position reporting services
AMTS Frequency Bands
AMTS operates in the 216–220 MHz band (formerly TV channels 13 and below) and in portions of the VHF maritime band. The FCC allocated these frequencies specifically for AMTS to provide a dedicated infrastructure service separate from the conventional marine VHF band used for ship-to-ship and ship-to-shore voice communications.
Who Operates AMTS Systems?
AMTS licenses are held by companies that operate base station networks serving maritime users. These are not individual vessel licenses — they are licenses for the shore-based infrastructure. Commercial operators provide AMTS service to subscribing vessels, similar to how cellular carriers provide coverage to phone users. AMTS licenses appear in the FCC ULS under the AMTS radio service code (WX) and can be researched using the FCC's database tools.
AMTS vs AIS
AMTS should not be confused with AIS (Automatic Identification System), which is the mandatory vessel tracking system using VHF channels 87B and 88B. AIS is a safety system; AMTS is a communications infrastructure service. Many commercial vessels use both systems for complementary purposes.