Iridium GMDSS Service
Iridium satellite service recognised by IMO since 2020 for GMDSS Sea Areas A1–A4, including polar regions.
In practice
Increasingly common alongside Inmarsat-C; offers polar coverage. Bridge officer monitors both terminals; both are tested at GMDSS daily check.
Regulatory detail & full definition
Iridium satellite service recognised by IMO since 2018 (Resolution MSC.99/22) as a GMDSS provider. Iridium provides distress alerting, safety information, and ship-to-shore distress communications across all GMDSS sea areas (A1–A4), including the polar regions where Inmarsat geostationary coverage is weak. The service complements rather than replaces Inmarsat-C. Approved Iridium GMDSS terminals carry IMO type approval and are integrated with the GMDSS-required equipment list under SOLAS Ch. IV. The polar coverage capability is particularly valuable for vessels operating under the Polar Code.
Authoritative source: IMO Resolutions Index ↗
Related
Source: IMO MSC.99/22 (2018) recognising Iridium
High confidence
Editorial confidence: how we grade.