A chart shows where a ship can go. The Admiralty List of Radio Signals tells the bridge who to call on the way, on which channel, and when. Pilot boarding requests, VTS reporting points, NAVTEX schedules, MRCC contacts, and distress procedures all sit in its six volumes. When a port state control officer asks how the bridge team planned its VHF reports for an arrival, the ALRS is the publication that answers the question.
What Is the Admiralty List of Radio Signals (ALRS)?
The Admiralty List of Radio Signals is a series of nautical publications from the United Kingdom Hydrographic Office (UKHO) listing the radio services ships use worldwide. Six volumes, numbered NP281 to NP286, cover everything from coast radio stations and satellite services to time signals, weather broadcasts, GMDSS procedures, and port operations.
Three features set it apart from general radio references:
- Worldwide coverage, organized by region, so a vessel buys only the parts its trade needs
- Weekly corrections through ADMIRALTY Notices to Mariners, so the content stays current between editions
- A paper and a digital format, with the digital version sold as ADMIRALTY Digital Radio Signals (ADRS)
ALRS Volumes 1 Through 6: Which Volume Covers What
Bridge teams rarely need every volume at once. The table below maps each volume to the job it supports, based on the UKHO ALRS series description.
| Volume | Title | Parts | Use it for |
|---|---|---|---|
| 1 (NP281) | Maritime Radio Stations | 2 | Coast stations, satellite services, coastguard contacts, TeleMedical Assistance (TMAS), quarantine and pollution reports, anti-piracy contacts |
| 2 (NP282) | Radio Aids to Navigation, DGPS, Legal Time, Radio Time Signals, and Electronic Position Fixing | 2 | Racons, AIS AtoN, DGPS, standard and daylight saving times, radio time signals |
| 3 (NP283) | Maritime Safety Information Services | 2 | Weather and navigational warnings, NAVTEX and EGC broadcasts, radio-facsimile, submarine and gunnery warnings |
| 4 (NP284) | Meteorological Observation Stations | 1 | Worldwide met station listings |
| 5 (NP285) | Global Maritime Distress and Safety System | 1 | Distress and SAR procedures, MRCC and MRSC contacts, NAVAREA coordinators, SOLAS and ITU extracts |
| 6 (NP286) | Pilot Services, Vessel Traffic Services, and Port Operations | 8 | Pilot boarding, VTS procedures, ship reporting systems, port radio |
Volume 6 drives most day-to-day use. Its eight regional parts run from the United Kingdom and Ireland (NP286-1) through Europe, the Mediterranean and Red Sea, the Indian subcontinent and Australasia, the Americas, East Asia, Central and South America, and Africa.
Matching volumes to a vessel's trade
A practical starting point for most SOLAS vessels:
- Every ship: Volume 5 (NP285), because distress and SAR procedures apply wherever the ship trades
- Coastal and port work: the Volume 6 parts for every region on the planned route
- Weather and warnings: the Volume 3 part for the ocean areas transited
- Communications planning: the Volume 1 part for the region
- Time and position references: the Volume 2 part for the region
A container ship on a transpacific rotation needs the "Americas, Far East and Oceania" parts of Volumes 1, 2, and 3, plus the Volume 6 parts covering each port of call. A Mediterranean ferry needs a much narrower set. The full regional breakdown is listed in the ALRS collection.
Is the ALRS Mandatory Under SOLAS?
SOLAS does not name the ALRS by title. The obligation comes through two regulations. SOLAS Chapter V, Regulation 19.2.1.4 requires all ships to carry nautical charts and nautical publications for the intended voyage. Regulation 27 requires those publications, explicitly including "all other nautical publications necessary for the intended voyage," to be adequate and up to date.
A ship that has to report to a VTS, contact a pilot station, or monitor NAVTEX cannot plan those steps without a current radio signals list. For that reason, many flag administrations name the ALRS directly in their carriage lists. The Marshall Islands, for example, has listed ALRS Volumes 1 to 6 among nautical publications required under SOLAS V/19 and V/27. ANS maintains a summary of flag state carriage requirements alongside its overview of IMO publication carriage requirements.
Two points DPAs often miss:
- ALRS does not replace ITU service documents. Some administrations separately list the ITU List of Coast Stations and the ITU maritime manual under the Radio Regulations; Singapore's published carriage list is one example.
- Volume 5 should postdate GMDSS modernization. The amended SOLAS Chapter IV entered into force on 1 January 2024, so an NP285 edition older than that predates the current GMDSS framework. The current NP285 is the 7th Edition, 2026.
How Often Is the ALRS Updated?
UKHO corrects every ALRS volume through the weekly ADMIRALTY Notices to Mariners. New editions follow a rolling schedule, so different volumes carry different edition years. In the current ANS range, Volumes 1 and 3 are 6th Editions dated 2025, while Volume 2, Volume 4, Volume 5, and most Volume 6 parts are 7th Editions dated 2026.
For bridge audits and port state control, an inspector typically checks two things:
- The edition aboard is the current edition for that volume or part
- Weekly corrections have been applied and recorded up to the latest notice
A current edition with six months of missed corrections fails the "up to date" test in Regulation 27 as clearly as an outdated edition does. The ANS USCG port state control publications checklist covers how inspectors approach publication currency.
Digital vs Paper ALRS: What's Available
The ALRS is available in digital form as ADMIRALTY Digital Radio Signals (ADRS), part of the ADMIRALTY Digital Publications (ADP) portfolio. ADRS is sold in three products: Volumes 1, 3, 4, and 5 combined; Volume 2; and Volume 6. The digital ALRS is not part of the ADMIRALTY e-Nautical Publications (AENP) e-book range, which covers titles such as Sailing Directions and the Nautical Almanac. Buyers browsing the AENP collection for radio signals should look under ADP instead.
| Factor | Paper ALRS | ADRS (digital) |
|---|---|---|
| Corrections | Applied by hand from weekly notices | Downloaded and applied electronically |
| Search | Index and regional diagrams | Search by text, position, or graphic window |
| Purchase unit | Individual volumes and parts | Bundled by volume group |
| Flag acceptance | Universal | Widely accepted; confirm with the administration |
Many flag states accept ADP in place of paper, but acceptance is set by each administration. The ANS comparison of ADMIRALTY digital publications and paper SOLAS compliance explains how to confirm it. Digital volumes are listed in the ADMIRALTY Digital Radio Signals collection. Radio equipment checks are covered separately in the GMDSS radio equipment inspection checklist.
Shop the Admiralty List of Radio Signals
The right ALRS set depends on the vessel's trading pattern, the flag's carriage list, and whether the bridge runs paper or ADP. Matching the parts to the route before the next audit avoids both gaps and unnecessary volumes.
Shop the Admiralty List of Radio Signals at amnautical.com, or contact ANS at +1 (954) 522-3321 or sales@amnautical.com to confirm the current editions for a specific route.
Frequently Asked Questions
What is the Admiralty List of Radio Signals?
The ALRS is a six-volume UKHO publication series (NP281 to NP286) listing maritime radio services worldwide, including coast stations, time signals, safety broadcasts, GMDSS procedures, pilot services, VTS, and port operations.
Is the ALRS mandatory under SOLAS?
SOLAS requires adequate, up-to-date nautical publications for the intended voyage under Chapter V, Regulations 19.2.1.4 and 27, without naming the ALRS. Many flag administrations list the ALRS by name as the publication that meets that requirement.
How often is the ALRS updated?
Weekly, through ADMIRALTY Notices to Mariners. UKHO also publishes new editions of each volume on a rolling schedule, so edition years differ between volumes.
Can the ALRS be carried digitally instead of in print?
Yes, as ADMIRALTY Digital Radio Signals within ADP, where the flag state accepts it. Many administrations do, but acceptance should be confirmed for each flag.
Which ALRS volume covers GMDSS?
Volume 5 (NP285) covers GMDSS, including distress and SAR procedures, MRCC contacts, NAVAREA coordinators, and relevant SOLAS and ITU extracts.
Which ALRS volume covers pilots and VTS?
Volume 6 (NP286), in eight regional parts, covers pilot services, vessel traffic services, ship reporting systems, and port operations.
