Real-time AIS vessel tracking, explained for anyone — no maritime background required.
The Automatic Identification System (AIS) is a VHF radio system that broadcasts a vessel's identity, position, course, and speed several times a minute. It was originally mandated by the IMO for collision avoidance, but the same broadcasts have become the backbone of modern maritime situational awareness.
Every AIS message carries a MMSI (the vessel's unique 9-digit ID), latitude and longitude from onboard GPS, speed over ground (SOG), course over ground (COG), and heading. Class A transponders (commercial ships) report as often as every 2 seconds when moving; Class B units (smaller craft) report less frequently.
Shore-based receivers and satellites pick up these VHF broadcasts and forward them to aggregators. Our AIS Intelligence API records every fix across 17 North Pacific ports 24/7, stores a 400-day archive, and exposes it as clean JSON. You can pull live positions, a vessel directory, or a full historical track for any MMSI.
AIS reception is line-of-sight. A vessel in open Bering Sea may only be seen by satellite passes; one in a deep Southeast Alaska fjord may drop out entirely. Knowing where a provider actually has receivers is the difference between useful data and a map full of holes — which is exactly why we built coverage specifically for Alaska, Hawaii, and the Pacific Northwest.