What the IMO adopted
In May 2026, the International Maritime Organization adopted the International Code of Safety for Maritime Autonomous Surface Ships, commonly called the MASS Code. It took effect on 1 July 2026. The code provides a common safety framework for commercial ships where autonomous or remote technology performs functions normally handled by crew on board.
The framework covers design, approval, certification and operation. It addresses navigation, connectivity, remote control, cybersecurity, fire safety, search and rescue, and the human roles that remain responsible for the vessel. Its goal is straightforward: an autonomous ship should meet a level of safety, security and environmental protection comparable with a conventional ship.
For now, the code is non-mandatory. IMO member states and operators can apply it, test it and report practical experience. That evidence will shape the mandatory version planned for the next decade. Existing requirements under the International Convention for the Safety of Life at Sea and other maritime rules continue to apply.
Autonomous does not mean unregulated
A ship does not qualify as a MASS simply because it uses advanced navigation software. It must complete the relevant approval process, hold a valid MASS Safety Certificate and operate within defined limits. Conventional safety and environmental duties still apply.
What counts as an autonomous ship
Shipping already uses automation for route planning, engine control, collision warnings and cargo monitoring. That alone does not turn a vessel into an autonomous ship under the code. IMO describes a MASS as a ship that can, to varying degrees, operate independently of human interaction because autonomous or remotely controlled systems replace or support functions normally performed by onboard crew.
A single vessel may also use different operating modes during one voyage. It could sail under direct onboard control in a busy port, use automated navigation in open water and receive support from shore in another phase. The code therefore focuses on the functions being performed, the operating conditions and who has authority at each point, rather than applying a simple crewed or crewless label.
- Automated support: software assists the crew, but people on board remain in direct control.
- Remote operation with crew aboard: a shore team can control certain functions while onboard personnel remain available.
- Remote operation without crew aboard: trained operators control the ship from a certified shore facility.
- Higher autonomy: onboard systems can make and carry out operational decisions within approved limits.
These descriptions are useful for understanding the progression, but the adopted code requires each ship to document its actual modes of operation and safe operating envelope. A marketing claim about an AI-powered vessel is not enough. Certification depends on what the technology controls and how risks are managed when equipment, communications or operating conditions fail.
The master still carries responsibility
One of the most important points in the MASS Code is that human accountability remains. The ship's master keeps overall responsibility even when the master is not physically on board. Remote operators and onboard crew also need defined duties that match the vessel's operating mode.
Remote Operations Centres are central to that model. These shore facilities may monitor or control some or all vessel functions. They need trained personnel, assessed systems and a certified safety-management structure. Reliable communications matter because a remote team cannot safely operate a ship if it loses an essential data or control link without a tested fallback.
The ship must also have a defined operating envelope. That can include limits for wind, sea state, visibility, water depth, weather and time of day. The operator must state what happens when conditions move outside those limits. A safe response could mean handing control to a person, slowing down, holding position or moving to a safe state, depending on the ship and situation.
Which cargo ships the code covers
The MASS Code applies to cargo ships covered by SOLAS Chapter I, generally ships of 500 gross tonnage or more on international voyages. IMO also recommends that member states apply it where practical to autonomous cargo ships below 500 gross tonnage.
That scope matters because many early autonomous projects are small, specialised or domestic. A short-sea feeder, harbour vessel or coastal cargo service can face a different approval path from a large ship trading internationally. Cargo owners should not assume that one pilot project proves readiness across deep-sea container networks.
IMO also states that there are currently no commercially operating, internationally trading SOLAS cargo ships that operate autonomously or by remote control. Trials have shown that larger remote and autonomous vessels are technically feasible, but the commercial fleet is expected to adopt the technology gradually. Mixed operation, with conventional and increasingly automated ships sharing the same routes and ports, is the more realistic near-term picture.
What changes for cargo owners today
For most shippers, the immediate answer is: very little changes in the booking process today. You still contract with a carrier or forwarder, receive transport documents, follow carrier milestones and manage customs, insurance and delivery in the usual way. The code regulates vessel safety and operation; it does not create a new cargo-booking contract or transfer operational responsibility to the shipper.
The practical questions will grow as carriers place certified autonomous or remotely operated vessels into service. Your procurement, insurance and risk teams may need to understand where the technology is used and how the carrier handles a loss of connectivity, cyber incident, remote-centre outage or handover between operating modes.
- Service scope: Is the autonomous vessel used on the main ocean leg, a feeder leg or only within a port area?
- Certification: Does the vessel hold the required MASS Safety Certificate for its declared modes of operation?
- Human control: Who is the master, where are the responsible operators and how is control transferred?
- Fallback operation: What happens after a communication, sensor, power or software failure?
- Cybersecurity: How does the operator protect command, navigation and cargo-related systems from interference?
- Incident communication: How and when will cargo interests receive updates after an operational exception?
Cargo visibility becomes more important, not less
A more automated ship may generate more operational data, but that does not guarantee clearer information for the cargo owner. Vessel telemetry and container milestones answer different questions. The carrier may know the ship's precise operating mode while a consignee still needs to know whether a specific box was loaded, transhipped, discharged or made available for pickup.
Shipment visibility therefore remains a separate requirement. Cargo teams need a consistent view of carrier events, route progress and changing arrival information, regardless of whether the vessel is conventionally crewed, remotely supported or autonomous. The useful outcome is not more raw technical data. It is a timely answer about what changed for the container and what action is required next.
Ship data is not shipment data
Knowing that an autonomous vessel is operating normally does not confirm that your container made the planned connection. Cargo owners still need container-level milestones, route changes and updated arrival information tied to the booked reference.
The regulatory timetable to watch
The present code is the start of an evidence-gathering period, not the end of the rulemaking process. The IMO roadmap sets out three important next steps:
- December 2026: the Maritime Safety Committee is expected to develop the framework for an experience-building phase.
- 2028: IMO plans to develop the mandatory MASS Code using operational evidence and work from its safety, legal, facilitation and environmental committees.
- By 1 July 2030: the organisation expects to adopt the first mandatory global MASS Code, with entry into force planned for 1 January 2032.
Those dates are targets and can change as the work develops. The experience-building phase is particularly important because it will expose how the framework performs outside controlled trials. Ports, flag states, coastal authorities, shipowners, remote operators and insurers all need workable answers before autonomous vessels can scale across international services.
How to prepare without overreacting
You do not need a separate autonomous-shipping policy for every booking in 2026. A better approach is to add a few technology-neutral checks to carrier procurement and incident planning. Ask how the carrier maintains control, protects critical systems, communicates exceptions and preserves cargo visibility. Those questions are useful on conventional ships too.
Keep contract and insurance reviews tied to an actual service rather than a general claim about autonomy. If a carrier introduces a MASS vessel on your lane, confirm the certified operating modes, geographic scope and responsibility chain. Then make sure your tracking process can continue to follow the container across every conventional and autonomous leg of the journey.
The bottom line
The IMO MASS Code gives autonomous cargo shipping a credible global safety framework for the first time. It took effect on 1 July 2026, remains voluntary and is intended to prepare the industry for mandatory rules targeted for 2032. It does not mean international container fleets have become crewless. For cargo owners, the sensible response is to watch certified deployments, ask carriers clear questions about control and fallback procedures, and keep container-level visibility independent of the technology operating the ship.