If you operate a SOLAS-class vessel out of Singapore, GMDSS is not optional. The Global Maritime Distress and Safety System is the international rule book that says — in plain language — if your ship is in trouble, you must have the equipment to call for help and you must keep it working. The Maritime Port Authority of Singapore (MPA) enforces this on every vessel flying the Singapore flag.

This guide is the same checklist we hand to fleet operators preparing for a flag survey or a port state control inspection. It covers what is actually required, what is optional but smart, and which compliance traps fail vessels every year.

Who Has to Comply

• All cargo ships of 300 GT and above on international voyages.
• All passenger ships on international voyages, regardless of size.
• Singapore-flagged vessels operating internationally are governed by SOLAS Chapter IV and MPA Shipping Circulars.
• Smaller domestic vessels are not GMDSS-mandated, but many shipowners still equip them voluntarily for safety and insurance reasons.

If you are not sure whether your vessel is in scope, the safest answer is: ask your flag inspector, or send us your IMO number and we will tell you for free.

The Four Sea Areas

GMDSS equipment requirements scale up with how far your vessel operates from shore. The sea area determines the minimum equipment list.

Sea area	Definition	Typical SE Asia example
A1	Within VHF coastal radio coverage (~20–30 NM from shore)	Singapore Strait day-trippers, harbour craft, near-shore tugs
A2	Beyond A1, within MF coastal radio coverage (~100–150 NM)	Coastal trades between Singapore, JB, Batam, Bintan
A3	Beyond A2, within Inmarsat geostationary satellite coverage (roughly 76°N to 76°S)	Most international trades from Singapore — SE Asia, India, Middle East, Australia
A4	Polar regions outside Inmarsat coverage	Rare for Singapore vessels — expedition or polar charter only

Minimum Equipment by Sea Area

The list below is the practical minimum. Always cross-check against your specific MPA Shipping Circular and class society survey notes — configurations change for passenger ships, tankers, and ships carrying more than 12 passengers.

Sea Area A1

• VHF radio with DSC (Class A or B)
• NAVTEX receiver
• 406 MHz EPIRB, registered with MPA
• SART or AIS-SART (one for vessels under 500 GT, two for 500 GT and above)
• Two or three two-way handheld VHF radios (depending on tonnage)

Sea Area A2

Everything in A1, plus:

• MF radio with DSC, or an Inmarsat C terminal that meets the A2 carriage requirement

Sea Area A3

Everything in A1 and A2, plus a recognised long-range distress communication path. There are now two compliant options:

• Inmarsat C — the long-standing GMDSS satellite path, still the most widely fitted in 2026.
• Iridium GMDSS — approved as an alternative GMDSS satellite service. Useful for vessels that need pole-to-pole coverage or want a smaller, lower-power install.

Or alternatively, an MF/HF radio with DSC capability for the long-range link.

Sea Area A4

Polar operations require MF/HF DSC and, in practice, an Iridium GMDSS terminal because Inmarsat C does not cover the poles.

Iridium GMDSS or Inmarsat C: Which to Specify in 2026

For a Singapore-flagged vessel trading SE Asia, India, the Middle East, or Australia, both options are now viable. Operators are increasingly choosing Iridium GMDSS where it makes sense because:

• Pole-to-pole coverage with no “dead zone” near 76° of latitude.
• Smaller, lower-power terminal — useful on retrofits.
• Faster connection times for distress voice.

Inmarsat C remains the established choice and integrates well with existing MF/HF and bridge consoles. For a new build or a major refit, the call is usually based on the rest of the comms stack on the bridge. We can advise on the specific make and model that fits your survey.

EPIRB and SART: The Two Items That Fail Inspections Most Often

• EPIRB battery and hydrostatic release. Both have expiry dates. A surveyor will check both. Plan replacements 60 days before expiry.
• EPIRB registration. A 406 MHz EPIRB must be registered with the relevant national authority — for Singapore-flagged vessels, this is MPA. An unregistered or wrongly-registered EPIRB triggers a deficiency at port state control.
• AIS-SART vs radar SART. Both are still legal. Most operators have moved to AIS-SART for ease of use, but an old radar SART is still compliant if its battery is in date.
• Annual radio survey and approved service report. A GMDSS-class vessel must hold a valid Radio Safety Certificate, renewed annually. The hardware can be perfect; missing paperwork still fails the inspection.

MPA Singapore-Specific Notes

• Equipment must be type-approved by an MPA-recognised standard (typically IMO MSC resolutions, with class society endorsement from BV, DNV, ABS, LR, or NK).
• Annual radio survey is performed by an MPA-authorised radio surveyor.
• EPIRB registration is online via the MPA portal — do this before the EPIRB ever leaves the workshop.
• The Battery Replacement Date sticker on every battery must match the actual installed battery; surveyors do check.

Related Reading

• Iridium 9555 vs IsatPhone 2 for SE Asia Fishing Fleets
• Starlink Maritime in Singapore: Plans, Pricing, and How to Buy
• Maritime IoT and Fleet Management Buyer’s Guide
• VMS Indonesia: What Fishing Vessel Owners Need to Know in 2026

How to Source GMDSS Equipment in Singapore

Envision Data supplies type-approved GMDSS hardware and consumables in Singapore: 406 MHz EPIRBs, AIS-SARTs, two-way handheld VHF, MF/HF DSC and NAVTEX receivers, Inmarsat C and Iridium GMDSS terminals, plus replacement batteries and hydrostatic releases. We work alongside MPA-authorised radio surveyors so the paperwork lines up with the hardware on the day of the survey.

Send us your vessel particulars — tonnage, sea area, year of last radio survey, and current GMDSS equipment list — and we will reply with a prioritised quote that meets your next survey deadline. Email sales@envisiondatasg.com or WhatsApp +65 9088 4899.