Nautical Wing
Radiocommunications
The Directorate General of Maritime Administration (DGMA) administers India's obligations under SOLAS Chapter IV on Radiocommunications, giving effect to the Global Maritime Distress and Safety System (GMDSS) through the Merchant Shipping (Distress and Safety Radio Communication) Rules, framed under the Merchant Shipping Act, 2025. The Nautical Adviser to the Government of India is the Approving Authority and Competent Authority for all matters relating to GMDSS equipment approval, radio surveys, approved service stations, and satellite service recognition for Indian-flagged vessels.
Satellite GMDSS
DSC Radio
EPIRB Distress
The Nine Functional Requirements of GMDSS
SOLAS IV Reg. 4 / MS (D&S Radio) Rules 2025, Rule 71
Distress Alert Ship to Shore
2
Distress Alert Shore to Ship
3
Distress Alert Ship to Ship
4
SAR Coordination Communications
5
On-Scene Communications
6
Locating Signals (EPIRB / SART)
7
Maritime Safety Information (MSI)
8
General Radiocommunications
9
Bridge-to-Bridge Communications
GMDSS Sea Areas and India's Coastal Coverage
GMDSS Sea Area Definitions and India's Operational Context
SOLAS IV Reg. 2 / MS (D&S Radio) Rules 2025, Rule 4(56–59)The GMDSS defines four sea areas, each carrying distinct equipment carriage requirements. India's coastal Sea Area A1 is defined by the VHF DSC coverage of India's coast stations, typically extending 20 to 50 nautical miles from the coast. Sea Area A2 extends to the limit of MF coverage. The bulk of India's international fleet operates in Sea Area A3, covered by Inmarsat (approximately 70°S to 70°N) and, for ships fitted with Iridium SES, globally including polar regions. As revised from 1 January 2024, the coverage of Sea Area A3 is vessel-specific, determined by the RMSS Ship Earth Station carried on board. The Indian Administration has confirmed through DGS Circular 23/2024 that both Inmarsat and Iridium are recognised RMSS for Indian-flagged vessels. Thuraya is not a recognised RMSS and its use in Indian waters is prohibited under DGMA Order No. 09 of 2023.
A1
VHF Coverage (Coastal India)
Within radiotelephone coverage of at least one VHF coast station where continuous DSC alerting is available. In India, coast radio stations at Mumbai (VWB), Chennai (VWC), Kolkata (VWD), Visakhapatnam, Kochi, Goa, Mundra, Tuticorin, Port Blair and others define the A1 zone. Typically 20 to 50 nautical miles from shore.
India-Specific
A2
MF Coverage (Extended Coastal)
Excluding Sea Area A1, within MF radiotelephone coverage with continuous DSC alerting. Extends to approximately 150 to 400 nautical miles from the Indian coast. Indian vessels on near-coastal international voyages to neighbouring countries such as Sri Lanka, Maldives, Bangladesh and Myanmar commonly operate in A2.
Primary Equipment
A3
RMSS Coverage (Deep Sea)
Excluding A1 and A2, within the coverage of the RMSS SES carried on board. The majority of India's international trading fleet, operating on routes to the Persian Gulf, East Africa, Southeast Asia and Europe, falls within A3. From 1 January 2024, DGS Circular 23/2024 requires Indian A3 ships without an SES to install at least one Inmarsat or Iridium RMSS SES.
India-Specific (DGS Cir. 23/2024)
A4
Polar and Remote Areas
Outside A1, A2 and A3. Relevant for Indian vessels on trans-polar routes and those serving India's polar research programmes at Maitri (Antarctica) and Himadri (Arctic). The Indian research vessel RV Sagar Nidhi and supply vessels for research stations must meet A4 HF requirements. Ships fitted with Iridium SES do not face a separate A4 regime as Iridium covers polar regions.
Primary Equipment
India's State Obligations and DGMA Functions
India's Obligations as a Contracting Government
SOLAS IV Reg. 5 / MS (D&S Radio) Rules 2025, Rule 9Shore-Based Radiocommunication ServicesRule 9, MS (D&S Radio) Rules 2025
- India maintains coast radio stations at Mumbai (VWB), Chennai (VWC), Kolkata (VWD), Visakhapatnam, Kochi, Goa, Mundra, Porbandar, Tuticorin and Port Blair providing continuous VHF DSC watch on Channel 70 and MF DSC watch on 2187.5 kHz
- Indian Coast Guard maintains maritime distress watch and operates as the Maritime Rescue Coordination Centre (MRCC) for India, coordinating with Maritime Rescue Sub-Centres (MRSCs) at Goa, Visakhapatnam, Chennai, Port Blair, Mumbai and Noida
- NAVAREA VIII (Indian Ocean region) is coordinated by the National Hydrographic Office, Dehradun, under arrangements with the India Meteorological Department for meteorological MSI content
- NAVTEX service broadcasts on 518 kHz (English) and 490 kHz (regional languages) from coastal transmitting stations, covering India's Exclusive Economic Zone and adjacent sea lanes
- COSPAS-SARSAT 406 MHz EPIRB alert processing: India operates a Local User Terminal (LUT) and Mission Control Centre (MCC) within the COSPAS-SARSAT system, ensuring rapid alert forwarding to the Indian Coast Guard MRCC for search and rescue initiation
- Mobile Ship Station Licences are issued by the Wireless Planning and Coordination (WPC) Wing of the Ministry of Communications to all Indian-flagged vessels
India Authorities
Radio Survey and Safety Radio CertificationMS (D&S Radio) Rules 2025, Rules 26–30
- Every Indian vessel to which the Rules apply must hold a valid Cargo Ship Safety Radio Certificate or, for passenger ships, a Passenger Ship Safety Certificate with a valid radio component, issued by DGMA following a satisfactory radio survey
- Radio surveys conducted by Nautical Surveyors of DGMA at the offices of Principal Officers of Mercantile Marine Departments at Mumbai, Kolkata, Chennai, Kochi and Kandla, and by Recognised Organisations authorised by DGMA
- Annual Radio Survey required to maintain validity; initial, renewal and intermediate surveys conducted per the regime applicable to the vessel's size and trading area
- The Record of Equipment (Form R) forming part of the Cargo Ship Safety Radio Certificate must be kept current and reflect the actual GMDSS installation on board at all times
- Approved Service Stations listed on the DGMA website must conduct all equipment testing, EPIRB annual testing, VDR annual performance testing and SART functional tests and issue test certificates retained on board
- MMSI numbers for Indian vessels are assigned and registered with the ITU Maritime Mobile Access and Retrieval System (MARS) database through the Wireless Planning and Coordination Wing using the Indian MID prefix 419
Certificates Issued by DGMA
Ship Radio Installation Requirements: Indian Fleet
Ship Radio Installation and Equipment Carriage for Indian Vessels
MS (D&S Radio) Rules 2025, Rules 12–25Minimum Equipment: All GMDSS ShipsRule 12 / SOLAS IV Reg. 7
- VHF radio installation: DSC on Channel 70 and radiotelephony on Channels 16, 13 and 6; continuous DSC watch on Channel 70 maintained from the navigating bridge at all times
- MSI and SAR information receiver for the entire voyage: NAVTEX receiver in areas where NAVTEX service is provided (covering India's coastal waters and the Indian Ocean shipping lanes); RMSS-EGC receiver beyond NAVTEX coverage
- Satellite EPIRB on 406 MHz, COSPAS-SARSAT compatible, float-free hydrostatically released installation near the navigating bridge; serial number and MMSI to be programmed and registered with the WPC Wing and COSPAS-SARSAT
- SART or AIS-SART: cargo ships of 300 to 499 GT carry 1 set; cargo ships of 500 GT and above and all passenger ships carry 2 sets (effective 1 January 2024, consolidated from Chapter III)
- Two-way VHF radiotelephone apparatus: cargo ships of 300 to 499 GT carry 2 sets; cargo ships of 500 GT and above and passenger ships carry 3 sets (effective 1 January 2024, consolidated from Chapter III)
- All radio equipment to be approved by or on behalf of the Nautical Adviser to the Government of India; equipment must carry a valid type approval certificate from the Approving Authority
India-Specific Note
Sea Area A3: Post-2024 Equipment Combination for Indian ShipsRule 15 / DGS Circular 23/2024
- The Indian Administration, through DGS Circular No. 23 of 2024, has specified that following the removal of NBDP from the GMDSS requirements, the accepted combination for Indian ships operating in Sea Area A3 is: (1) two VHF radio installations; (2) one MF/HF radio installation (MF/HF accepted in place of a separate MF installation); and (3) one Inmarsat or Iridium RMSS Ship Earth Station
- Indian ships in A3 previously holding only MF/HF equipment and no RMSS SES must install at least one RMSS SES; compliance to be verified at the next annual radio survey
- For A3 duplication purposes, a single MF/HF installation may serve as both the primary MF radio and the duplicated MF/HF radio, per COMSAR.1/Circ.32/Rev.3
- Iridium GMDSS terminals are accepted for fixed installation on Indian ships exclusively for distress and safety communications under DGMA Order No. 09 of 2023 and DGMA Order No. 02 of 2026; ships using Iridium SES may treat their Sea Area A3 as covering the entire globe including polar regions
- Thuraya equipment is prohibited in Indian waters under all circumstances and is not recognised as an RMSS by the Indian Administration
- Personal portable satellite communication devices (Thuraya, portable Iridium handsets, Zoleo and equivalent) must be declared in the Pre-Arrival Notification of Security (PANS) and are subject to sealing by port authorities on arrival in Indian ports
Key Circulars
Maintenance Obligations and Approved Service StationsRules 20–25, MS (D&S Radio) Rules 2025
- Three methods of maintenance accepted by the Indian Administration: at-sea maintenance by a qualified Electro-Technical Officer or GMDSS-qualified maintainer; duplication of all mandatory equipment; or shore-based maintenance under a valid Shore-Based Maintenance Contract with an Approved Service Station
- A "Shore-Based Maintenance Contract" under the Rules means a document signed between the vessel's owner and a service provider authorised by the equipment manufacturer and approved by DGMA, conforming to IMO standards
- All annual performance testing of GMDSS equipment including EPIRB (406 MHz battery, hydrostatic release and coding checks), SART (power output and operational frequency), VDR and S-VDR (annual performance test per Resolution MSC.214(81)) must be carried out by an Approved Service Station
- Test certificates issued by Approved Service Stations must be retained on board and produced at every radio survey; absence of a valid test certificate constitutes a deficiency under Port State Control inspections
- The consolidated List of Approved Service Stations maintained by DGMA is available for download from the DGMA website; ship owners are responsible for verifying current approval status before engaging any service provider
Download
GMDSS Radio Personnel Requirements for Indian ShipsDGS Safe Manning Circular 54/2025
- Every Indian ship to which the Rules apply must carry radio personnel qualified for distress and safety radiocommunication purposes as specified in DGS Safe Manning Circular No. 54 of 2025 issued under SOLAS Regulation V/14
- For international voyages (A2, A3, A4): either one dedicated Radio Officer holding a valid Indian GMDSS Certificate of Competency (CoC) or two deck officers holding valid Indian GMDSS CoCs are required to be carried at all times
- For coastal voyages (A1): at least one officer holding a valid Indian GMDSS CoC; for vessels below 500 GT on coastal voyages, at least one officer holding a valid Restricted Operator Certificate (ROC)
- GMDSS CoC and ROC issued by DGMA through the seafarer certification examination system, pursuant to STCW Regulation IV/2; CoCs to be revalidated every five years in accordance with STCW requirements
- Passenger ships must designate a specific officer with primary responsibility for all radiocommunications during distress incidents; the designated officer's name to be entered in the radio log and posted at the communications station
- False distress alerts constitute a serious offence under the MS Act, 2025; GMDSS operators are personally responsible for the accuracy of all DSC calls, EPIRB activations and any emergency transmissions
India Certificates
Radio Log and False Distress ObligationsRules 31–34, MS (D&S Radio) Rules 2025
- A radio log in the format prescribed by DGMA must be maintained on every vessel to which the Rules apply; the log must identify the vessel by name, call sign and MMSI on every page
- Entries to include: daily equipment checks; battery condition and charge test results; all distress, urgency and safety communications transmitted and received; the name of the operator on duty; and all EPIRB, SART and two-way VHF radiotelephone functional test dates
- The passenger ship radio log must additionally record the name of the officer designated with primary distress communication responsibility
- All entries to be made in ink or indelible pencil; corrections by single line crossing-out with the correct entry alongside; no erasures; the log must be retained on board for a minimum of two years
- Under the MS (D&S Radio) Rules 2025, a "False Distress" alert transmitted inadvertently or otherwise imposes an obligation of immediate cancellation and reporting to the nearest MRCC; failure to cancel or report is an offence under the Merchant Shipping Act, 2025
- The Indian Coast Guard MRCC must be notified immediately of any inadvertent EPIRB activation and a false distress report filed in the prescribed form; penalties under both the MS Act 2025 and the Indian Telecommunications Act 2023 may apply
Reporting Authority
Energy Sources and Performance StandardsRules 17–19, MS (D&S Radio) Rules 2025
- Two independent sources of electrical energy to supply the complete GMDSS installation: the ship's main electrical supply and an emergency source (batteries or emergency generator)
- Emergency source capacity: minimum one hour for vessels operating in Sea Area A1; minimum three hours for vessels in A2, A3 and A4; batteries to be tested and charge verified at each annual radio survey
- All radio equipment installed on or after 1 January 2024 to conform to revised IMO performance standards adopted by MSC.511(105), MSC.512(105) and MSC.513(105); equipment meeting former standards may be installed until 1 January 2028 per MSC.1/Circ.1676 subject to DGMA acceptance
- VHF radio equipment to support new 4-digit channel display format per ITU Radio Regulations Appendix 18; implementation for new installations extended to 1 January 2028 per MSC.1/Circ.1460/Rev.4
- NAVDAT (500 kHz and 4226 kHz) is recognised under the Rules as an international automated digital service for MSI promulgation; Indian ships should equip MSI receivers capable of receiving NAVDAT broadcasts as the service expands in the Indian Ocean region
- VDES (VHF Data Exchange System) is defined in the Rules as a radio communication system operating on AIS, ASM and VDE frequencies; carriage requirements will be notified by DGMA when the system becomes operational in Indian waters
IMO References
MMSI Numbers and Indian Coast Radio Stations
Indian Coast Radio Stations and MMSI Registration
WPC Wing, Ministry of Communications / ITU MARSMumbai (VWB)
004195000
Major coast radio station; DSC watch VHF Ch 70 and MF 2187.5 kHz; coordinates with Mumbai MRSC
Chennai (VWC)
004192000
Coast radio station; DSC watch VHF Ch 70; Bay of Bengal coverage; coordinates with Chennai MRSC
Kolkata (VWD)
004193000
Coast radio station; DSC watch; Bay of Bengal northern region; coordinates with Kolkata MRSC
Visakhapatnam
004194000
Coast radio station; east coast DSC coverage; coordinates with Visakhapatnam MRSC
Kochi (VWO)
004196000
Coast radio station; southwest coast and Arabian Sea coverage; coordinates with Kochi MRSC
Indian Fleet MMSI Format
419XXXXXX
MID prefix 419 assigned by ITU to India; all Indian ship MMSIs begin with 419; registration through WPC Wing, Ministry of Communications, New Delhi
Equipment Carriage Summary for Indian Fleet
GMDSS Equipment Carriage Requirements for Indian Vessels
MS (D&S Radio) Rules 2025, Rules 12–17 / COMSAR.1/Circ.32/Rev.3| Equipment | A1 | A2 | A3 | A4 | India-Specific Remarks |
|---|---|---|---|---|---|
| VHF Radio (DSC Ch 70, RT Ch 16, 13, 6) | ✓ | ✓ | ✓ | ✓ | 300–499 GT: 1 set; 500 GT and above and passenger ships: 2 sets. Continuous DSC watch on Ch 70. All VHF equipment to be approved by Nautical Adviser/DGMA. MMSI (MID 419) programmed and WPC licence current. Rule 12, 2025 Rules |
| Satellite EPIRB (406 MHz, COSPAS-SARSAT) | ✓ | ✓ | ✓ | ✓ | Hydrostatically released, float-free; MMSI and vessel details registered with WPC Wing and COSPAS-SARSAT India database. Annual battery, hydrostatic release and coding tests by Approved Service Station. Test certificate on board. VHF-EPIRB no longer accepted in A1. Rule 13, 2025 Rules |
| SART or AIS-SART | ✓ | ✓ | ✓ | ✓ | 300–499 GT: 1 set; 500 GT and above and passenger ships: 2 sets. Transferred from SOLAS Ch III to Ch IV effective January 2024. Annual functional test by Approved Service Station. Rule 12.3, 2025 Rules |
| Two-Way VHF Radiotelephone Apparatus | ✓ | ✓ | ✓ | ✓ | 300–499 GT: 2 sets; 500 GT and above and passenger ships: 3 sets. Transferred from SOLAS Ch III to Ch IV effective January 2024. Portable; for on-scene use in survival craft areas. Rule 12.4, 2025 Rules |
| MSI / SAR Receiver (NAVTEX or RMSS-EGC) | ✓ | ✓ | ✓ | ✓ | NAVTEX on 518 kHz (international, English) and 490 kHz (regional) covers Indian coastal waters and adjacent shipping lanes; RMSS-EGC receiver required beyond NAVTEX coverage. NAVDAT receiver recommended for Indian Ocean routes. HF NBDP no longer mandatory. Rule 12.2, 2025 Rules |
| MF/HF Radio (DSC 2187.5 kHz; multi-band) | ✓ | ✓ | ✓ | For A2 and above. Continuous DSC watch on 2187.5 kHz. Under DGS Cir. 23/2024, MF/HF installation accepted in A3 as the combined MF/HF requirement; HF NBDP optional. Single MF/HF unit accepted as both primary and duplicated MF/HF per COMSAR.1/Circ.32/Rev.3. DGS Cir. 23/2024 | |
| RMSS Ship Earth Station (Inmarsat or Iridium) | ✓ | * | Mandatory for A3 under DGS Cir. 23/2024. Both Inmarsat and Iridium are recognised RMSS for Indian ships. Thuraya is prohibited. Fixed Iridium GMDSS terminals for distress and safety only per DGMA Order 09/2023 and Order 02/2026. Iridium SES provides global A3 coverage including polar regions. DGS Cir. 23/2024 / DGMA Order 09/2023 | ||
| HF Radio (DSC, radiotelephony, 4–16 MHz) | * Opt 2 | ✓ | Mandatory for A4. Required for Indian polar research vessels and vessels on trans-polar routes. Frequencies: 4, 6, 8, 12 and 16 MHz DSC and voice bands. HF NBDP no longer mandatory for GMDSS; may be retained for MSI reception. Rule 17, 2025 Rules |
Applicable Regulations and DGS / DGMA Circulars
Key Regulations, Rules and Indian Administration Circulars
SOLAS Chapter IV, as revised by Resolution MSC.496(105) and in force from 1 January 2024, is implemented in India through the Merchant Shipping (Distress and Safety Radio Communication) Rules, 2025. A series of DGS and DGMA circulars, orders and notices give specific guidance to Indian shipowners, operators and masters. The key international and domestic instruments are set out below, with India-specific items highlighted in amber.
▶ International Instruments
SOLAS IV Reg. 1–4
Application, Definitions, Exemptions, Functional Requirements
Chapter IV applies to all passenger ships and cargo ships of 300 GT and above on international voyages. The nine functional requirements govern the complete GMDSS capability that every applicable Indian-flagged vessel must maintain at all times while at sea.
SOLAS IV Reg. 7
Radio Equipment: General (All Ships)
Minimum equipment for all GMDSS ships: VHF DSC, satellite EPIRB, SART or AIS-SART, two-way VHF radiotelephones and MSI/SAR receiver. SART and two-way VHF requirements consolidated from SOLAS Chapter III effective January 2024.
SOLAS IV Regs. 8–11
Additional Equipment by Sea Area (A1 to A4)
Tiered additional equipment requirements for each sea area. From January 2024, A3 ships without a RMSS SES must install one; HF NBDP removed as mandatory; VHF-EPIRB no longer accepted in A1. Sea Area A4 remains HF-primary except for vessels with global RMSS coverage.
SOLAS IV Reg. 15
Maintenance Requirements
Three approved methods: at-sea maintenance by qualified person; equipment duplication; shore-based maintenance contract. Indian ships in A3 and A4 must demonstrate compliance with one of these methods at every annual radio survey.
Resolution MSC.496(105)
GMDSS Modernisation (2022)
Adopted at MSC 105 in April 2022; in force 1 January 2024. Replaced all Inmarsat-specific references with RMSS; revised A3 definition; removed NBDP; consolidated SART provisions from Chapter III; updated performance standards framework.
COMSAR.1/Circ.32/Rev.3
Harmonisation of GMDSS Requirements (2024)
Supersedes Rev.2. Specifies that for Sea Area A3, two VHF radios, one MF/HF radio and one RMSS SES constitute a sufficient GMDSS installation. Confirms that a single MF/HF unit may serve as both primary MF and duplicated MF/HF.
▶ India-Specific Instruments
MS (D&S Radio) Rules 2025
Primary Indian Domestic Instrument
Framed under the Merchant Shipping Act, 2025. Supersedes the 1995 Rules and the Radio Direction Finders Rules, 1968. Applies to all Indian flag vessels and foreign flag vessels in Indian waters. Defines Approved Service Station, Approving Authority (Nautical Adviser), Shore-Based Maintenance Contract, MMSI, and all GMDSS equipment terms under Indian law.
DGS Circular No. 23/2024
Sea Area A3 Equipment Requirements for Indian Ships
Confirms that from 1 January 2024, NBDP is no longer a GMDSS requirement. Specifies the accepted A3 combination for Indian ships as two VHF radios, one MF/HF installation and one RMSS SES. Directs A3 ships without SES to install one. Both Inmarsat and Iridium are recognised RMSS.
DGS Safe Manning Circular 54/2025
GMDSS Radio Personnel Requirements
Specifies that on all Indian vessels, either one dedicated Radio Officer or two deck officers holding valid Indian GMDSS CoCs are required. For vessels below 500 GT on coastal voyages, at least one officer holding a valid Restricted Operator Certificate is required.
DGMA Order No. 09/2023
Iridium GMDSS and Thuraya Prohibition
Permits fixed Iridium GMDSS terminals on Indian ships exclusively for distress and safety communications under the RMSS framework. Prohibits Thuraya satellite equipment in Indian waters without any exceptions. Clarifications issued in November 2023 and March 2024 address the WMO Voluntary Observing Ship Scheme.
DGMA Order No. 02/2026
Satellite Communication Policy Update
Reaffirms the prohibition on Thuraya equipment and the acceptance of approved Iridium GMDSS terminals. Personal portable satellite phones, including portable Iridium handsets and Zoleo devices, must be declared in PANS and are subject to sealing on arrival at Indian ports. Non-compliance attracts penalties under MS Act 2025 Section 281(45) and Indian Telecommunications Act 2023 Section 31.
Approved Service Stations List
DGMA-Approved Service Stations for Radio and Navigational Equipment
The consolidated list of all service stations approved by the Nautical Adviser to the Government of India for testing, servicing and survey of GMDSS, VDR and navigational equipment. Ship owners must verify current approval status before engaging any service provider. Download List (PDF) ↗
