AIS (Automatic Identification System)
The radio transponder system that broadcasts a ship's identity, position, course and speed — and can mark a hazard with a virtual beacon.
AIS is carried by most large ships under SOLAS and by many smaller craft. It lets ships and shore stations see each other's identity and movement. AIS stations can also be fixed to buoys, wrecks and structures as aids to navigation, or broadcast a "virtual" aid that exists only as a symbol on radar and electronic chart displays.
In warnings, AIS appears in two ways: a new AIS aid marking a wreck or construction site, or an AIS station that has stopped transmitting.
What the archive shows
48 messages in this archive use “AIS (Automatic Identification System)”, the earliest issued 2004-12-18 and the latest 2026-09-18. 5 of them are in force in the latest lists we collected. A hazard reported again and again counts once per message.
The largest yearly count is 2008, with 7 messages. Collection is incomplete between 2024-05 and 2026-08-17, so 2024, 2025 and 2026 are not comparable with fully collected years.
Other accounts for 20 of 48 recorded messages (42%), the largest warning type group in this selection.
Located messages that use it fall in 15 sea areas; the most frequent are North Sea (6), Black Sea (6) and Persian Gulf (5).
By warning series: HYDROLANT 22, HYDROPAC 13, NAVAREA IV 6 and NAVAREA XII 3, and 2 more.
Messages using it, by year of issue
By month of issue, all years
Where it appears · 15 sea areas
In force now · 5
- AUSCOAST 297/26 · Other · Bass Strait2026-09-18 · in force
8 VIRTUAL AIS NAVIGATION MARKS IN AN AREA BOUNDED BY 38-23S TO 38-37S AND 148-25E TO 148-37E…
8 virtual AIS navigation marks in an area bounded by 38-23S to 38-37S and 148-25E to 148-37E inoperative → - UKWZ 471/26 · Other · North Sea2026-08-03 · in force
…NA GAOITHE WIND FARM. 1. NNG E BUOY 56-14.3N 002-08.6W AND NNG S BUOY 56-12.3N 002-09.8W AIS INOPERATIVE. 2. CANCEL WZ 396/26.
Neart na gaoithe wind farm → - UKWZ 455/26 · Nav aids · North Sea2026-07-22 · in force
FORTIES. BRITANNIA GAS FIELD. PLATFORM 16/26, 58-02.9N 001-08.3E, AIS INOPERATIVE.
Britannia gas field → - UKWZ 453/26 · Other · Celtic Sea2026-07-21 · in force
LUNDY. SAINT IVES NORTHWESTWARDS. WAVE HUB NW BUOY 50-23.1N 005-38.2W AIS INOPERATIVE.
Saint ives northwestwards → - HYDROPAC 627/26 · Nav aids · Gulf of Oman2026-03-03 · in force
ARABIAN SEA. GULF OF OMAN. STRAIT OF HORMUZ. U.A.E. DNC 10. GPS, GNSS, AND AIS INTERFERENCE REPORTED IN VICINITY OF FUJAIRAH (25-07.33N 056-20.05E). VESSELS ARE…
GPS, GNSS, and AIS interference reported in vicinity of fujairah (25-07.33N 056-20.05E) →
How it reads in recent messages
- HYDROPAC 2632/25 · Nav aids2025-10-13
PERSIAN GULF. RED SEA. STRAIT OF HORMUZ. GPS, GNSS AND AIS INTERFERENCE REPORTED IN VICINITY OF NORTH AND CENTRAL PERSIAN GULF, STRAIT OF HORMUZ…
GPS, GNSS and AIS interference reported in vicinity of north and central persian gulf, strait of hormuz and… → - HYDROPAC 1385/25 · Wrecks · Bass Strait2025-05-28
BASS STRAIT. AUSTRALIA. DNC 05. DANGEROUS WRECK MARKED BY VIRTUAL AIS "TB4" IN 38-34.91S 147-05.97E.
Dangerous wreck marked by virtual AIS "TB4" in 38-34.91S 147-05.97E → - NAVAREA IV 5/24 · Cable ops · North Atlantic Ocean2024-01-02
WESTERN NORTH ATLANTIC. TWO AIS BUOYS, BLACK, TEMPORARILY ESTABLISHED IN 33-49.80N 067-53.10W UNTIL FURTHER NOTICE BY…
Two AIS buoys, black, temporarily established in 33-49.80N 067-53.10W until further notice by cableship ile… →
Earliest in the archive
- NAVAREA IV 409/04 · Nav aids · Caribbean Sea2004-12-17
MASTERS AND OPERATORS OF VESSELS ARE ADVISED THAT AUTOMATIC IDENTIFICATION SYSTEM (AIS) OPERATION WITHIN 200 MILES OF 18-21-18.8N 064-56-48.5W IN ST. THOMAS, U.S. VIRGIN…
Masters and operators of vessels are advised that automatic identification system (AIS) operation within 200… →
Often in the same message
Related terms
- Virtual aid to navigation
- A buoy that exists only as an AIS signal — shown on electronic charts and radar, with nothing physically in the water.
- RACON (radar beacon)
- A radar beacon on a buoy, lighthouse or structure that answers a ship's radar with a Morse-code mark on the screen.
- GNSS / GPS
- Satellite positioning — GPS and other systems — and the testing, jamming and interference that make it unreliable in an area.
- Inoperative / unreliable / off air
- An aid or radio service is not working as charted or published.
Warning types that use it
- Nav aids — Lights extinguished, buoys off station, RACON/NAVTEX outages.
Counts cover the messages in this archive that use the term, recounted 2026-09-24; see coverage for what is collected and since when. Not for navigation — follow official NAVAREA and coastal broadcasts.