The IMO MASS Code:
Autonomous Ships Get Their First Rulebook
On 1 July 2026, international shipping entered a new regulatory era. The International Code of Safety for Maritime Autonomous Surface Ships (MASS Code) — adopted by the IMO's Maritime Safety Committee at its 111th session in May 2026 — became the world's first dedicated global framework for autonomous and remotely operated commercial vessels.
1. What the MASS Code Actually Does
The MASS Code is a goal-based framework, meaning it sets safety, security, and environmental protection outcomes rather than prescribing a single technical solution. It applies to cargo ships covered under SOLAS Chapter I and sets requirements across:
- Ship design and navigation systems
- Remote operations and connectivity
- Fire protection and search-and-rescue capability
- Cybersecurity of autonomous and remote systems
- Standards for shore-based Remote Operations Centres (ROCs), which are subject to certification by the flag administration
Vessels operating under the Code must still comply with SOLAS and other mandatory IMO instruments — autonomy does not exempt a ship from the safety standards expected of a conventionally crewed vessel.
📊 Key Fact
The MASS Code is currently non-mandatory. It marks the start of an Experience-Building Phase, during which member states test the framework ahead of a planned mandatory version.
2. The Four Degrees of Autonomy
The MASS Code recognises varying levels of autonomy, distinguished mainly by whether seafarers remain on board and where operational control sits. Notably, Degree 1 — a conventionally crewed ship using automated support such as ECDIS, autopilot, and collision-avoidance assistance — already describes much of today's modern commercial fleet. The more transformative categories, Degrees 3 and 4, involve remote or fully autonomous control with reduced or no crew on board, and remain far from routine deep-sea use.
3. The Road to Mandatory Rules
The IMO has published a clear, multi-year roadmap:
- 1 July 2026 — Non-mandatory MASS Code enters into effect
- December 2026 (MSC 112) — Framework developed for the Experience-Building Phase
- 2028 — Work begins on the mandatory MASS Code, incorporating lessons from the Experience-Building Phase and considering new SOLAS amendments
- By 1 July 2030 — Expected adoption of the mandatory MASS Code
- 1 January 2032 — Planned entry into force of mandatory rules
4. What This Means for Seafarers and Operators
For the vast majority of today's fleet and crew, nothing changes immediately — most commercial ships still operate at Degree 1, with full crews and traditional chains of command. What does change is the direction of travel:
- New competency areas are emerging around remote monitoring, autonomous system oversight, and shore-based Remote Operations Centre roles.
- Liability and insurance frameworks for higher degrees of autonomy remain unsettled — the current Code addresses functional safety requirements but does not resolve liability questions.
- Shore-based career pathways may expand as Remote Operations Centres require certified, trained personnel.
5. Frequently Asked Questions
Is the MASS Code mandatory?
Not yet. It is currently a non-mandatory instrument that came into effect on 1 July 2026. A mandatory version is targeted for adoption by 2030, entering into force on 1 January 2032.
Does the MASS Code allow fully unmanned ocean crossings now?
No. The Code establishes the regulatory foundation for autonomous operations, but the infrastructure, liability frameworks, and commercial confidence required for uncrewed deep-sea voyages are not yet in place. Most of the fleet operates at the lowest autonomy tier, where crews remain on board.
What ships does the MASS Code apply to?
It applies to cargo ships covered under SOLAS Chapter I engaged in international voyages.
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Join IAMP Today →Sources: International Maritime Organization (imo.org), DNV, Hill Dickinson. This article is for general information and does not constitute regulatory or legal advice.