The International Maritime Organization (IMO) is working toward a smooth transition to the next generation of navigation technologies.
The standard for Electronic Navigations Charts (ENCs) is transitioning from S-57, an older, static data standard to exchange digital hydrographic data, to the new S-100, a more dynamic framework. While S-57 was limited to just ENCs, the new S-100 framework can handle a variety of data types, such as real-time tides and currents, to improve situational awareness and safety.
IHO’s S-100 standard new possibilities
The S-57 specification is now frozen, offering stability but limiting any further development
As the current International Hydrographic Organization (IHO) standard for ENCs, S-57 enables features like alarms, real-time satellite positioning and route checks. But it is limited by a rigid structure, supporting only chart data. The S-57 specification is now frozen, offering stability but limiting any further development.
In contrast, IHO’s S-100 standard offers new possibilities by supporting multiple data layers such as bathymetry (S-102), water levels (S-104) and surface currents (S-111) – which together offer mariners richer situational awareness and improved decision making.
For example, dynamic under keel clearance can be visualised in real time alongside navigational data on Electronic Chart Display and Information Systems (ECDIS), supporting safer, more efficient route planning.
Integration of diverse marine data
The industry is currently in the testing and validation phase, ensuring the data meets user needs. Full adoption will take time as the ecosystem of systems, standards and workflows evolves.
S-100 provides a flexible, interoperable framework that enables the integration of diverse marine data – from bathymetry to weather and buoyage. By using a common framework, it ensures compatibility of product specifications across systems and supports the development of richer, more dynamic digital products.
ECDIS Performance Standards
For over 230 years, UKHO has been giving maritime data to help ships guide safely and trade efficiently
The IMO is supporting the transition to S-100 by updating (ECDIS) Performance Standards to require S-100 compatibility for all new installations (including retrofits) from January 2029. It has also designated the S-100 framework as the foundation for data exchange within its e-Navigation Maritime Services.
Working to support ongoing maritime needs, the United Kingdom’s Hydrographic Office (UKHO) is a world-pioneering centre for hydrography, supporting safe, secure, and thriving oceans through trusted data and marine geospatial insight. For over 230 years, UKHO has been delivering maritime information to help ships navigate safely and trade efficiently.
Adoption of marine data standards
Today, UKHO sources, processes, and delivers data through the ADMIRALTY portfolio, which is relied upon by over 90% of large ships trading internationally.
UKHO works with hydrographic offices, governments, defence, and industry to drive digital data access, to support the adoption of marine data standards like S-100, and to enable mariners, port operators and decision-makers to make safer, smarter choices worldwide.
Innovative maritime navigation solutions
UKHO is the UK's official source of marine charts and navigational data, helping ships navigate safely worldwide
The UKHO and the French Hydrographic Office (SHOM) are collaborating with four ECDIS manufacturers — Furuno, NAVTOR, OSI and 7Cs — to test S-100 data in live sea trials. “In doing so, we can test the practical use and display of this data in S-100-enabled ECDIS, as well as demonstrating the practical benefits in real-world scenarios,” says Thomas Mellor, UKHO's Head of Technical Partnerships.
The UKHO is the UK's official source of marine charts and navigational data, helping ships navigate safely worldwide. The UKHO delivers these quality, innovative maritime navigation solutions via its ADMIRALTY portfolio – made available to customers worldwide through a network of distributors.
Navigational solutions for crews and teams
NAVTOR is an ADMIRALTY Digital Distributor and an ECDIS manufacturer. As a distribution partner, NAVTOR relies on hydrographic data — like that produced by the UKHO — to deliver navigational solutions to crews and operations teams.
Through the IHO Geospatial Information Registry, organisations like the International Organization for Marine Aids to Navigation (IALA) and the World Meteorological Organization (WMO) can define their own data models.
These models can then be used to create S-100-compliant products, which integrate seamlessly into the wider ecosystem alongside official hydrographic data – enhancing situational awareness and decision-making for mariners.
Regulatory and operational needs
The two corps work near to align timelines, coordinate updates, and help with global implementation
While the IHO develops and maintains the S-100 framework, the IMO ensures these standards meet regulatory and operational needs – particularly under the International Convention for the Safety of Life at Sea (SOLAS) convention.
The two organisations work closely to align timelines, coordinate updates, and support global implementation. Their collaboration ensures that S-100 products and services enhance safety, support mariners, and foster wider digital innovation in navigation.
S-421 Route Plan standard
S-100 supports the exchange of non-geographic maritime data – such as voyage plans and route information – through the S-421 Route Plan standard. This enables vessels to share planned routes digitally with shore authorities and other ships, improving coordination, safety, and situational awareness.
Under the S-100 ECDIS Performance Standard, all systems must be capable of importing and exporting S-421 data. This allows for more efficient reporting, reducing communication overhead, and supporting smarter decision-making at sea.
Existing ECDIS systems
Wider adoption is expected through 2027 and beyond, as part of the phased S-100 rollout
S-421 has been published by the IHO and is available for implementation. Wider adoption is expected through 2027 and beyond, as part of the phased S-100 rollout.
Existing ECDIS systems in service will remain compliant; there are no plans to remove or retire them. However, from January 2029, all new and retrofit ECDIS must be built to support the S-100 Performance Standard — an important step towards long-term standardisation.
IHO international trial testbed standards
During the transition to S-100, we will see dual-fuel operation, says Mellor. “By this, we mean that systems will need to handle both the old S-57 charts and the new S-101 ENCs – therefore comprehensive testing and collaboration across the industry is key,” he says.
To support the transition, the UKHO is running S-100 ECDIS trials with other hydrographic offices, the Royal Navy, defence stakeholders and ferry operators, in accordance with IHO international trial testbed standards. This coordinated approach will help ensure interoperability and minimise disruption.
