IMO Set to Adopt First International Code for Autonomous Ships Next Month as Regulatory Race Accelerates

A Decades-Long Effort Reaches a Milestone

The International Maritime Organization’s Maritime Safety Committee is scheduled to convene its 111th session (MSC 111) in May 2026 with a singular objective at the top of its agenda: finalizing and adopting the first non-mandatory code governing Maritime Autonomous Surface Ships. If approved, the MASS Code would represent the first internationally coordinated attempt to regulate a class of vessels that, until recently, existed only in pilot programs and research papers.

The road to this point has been neither short nor smooth. The IMO first launched its regulatory scoping exercise for autonomous vessels in 2017, cataloguing gaps across safety, legal, and facilitation frameworks that existing maritime conventions were never designed to address. At MSC 110, held in June 2025, delegates completed work on the majority of the code’s chapters, covering areas from vessel design and construction to navigation, communication systems, and machinery. But the chapter on the human element — arguably the most contentious section, defining the role of remote operators, shore-based control centers, and residual crew requirements — was left unfinished and assigned to an intersessional working group that met in late September 2025.

The revised roadmap adopted at MSC 110 lays out an ambitious but measured timeline. Following the non-mandatory code’s expected adoption next month, MSC 112 in December 2026 will develop a framework for a structured Experience-Building Phase, during which flag states and operators will gather real-world operational data under the new guidelines. Development of a mandatory MASS Code, incorporating lessons from that phase, is set to begin in 2028, with adoption targeted by July 1, 2030, and entry into force on January 1, 2032.

What the Code Would Require

The MASS Code is structured as a goal-based instrument, meaning it sets safety outcomes rather than prescriptive technical specifications. This approach gives shipbuilders and operators flexibility in how they meet the standards, but it also introduces ambiguity that regulators and classification societies will need to resolve during implementation.

The code applies to vessels operating at varying degrees of autonomy, from ships with automated decision support systems where a human crew remains aboard, to fully autonomous vessels with no human presence on the bridge or anywhere else on the ship. A 2025 study on safety acceptance principles for autonomous ships published in Reliability Engineering and System Safety found that the concept of an “equivalent level of safety” — the principle that autonomous operations must be at least as safe as conventional crewed operations — is the most frequently cited acceptance standard in the emerging regulatory framework. The study also noted, however, that significant ambiguity remains around how to measure and demonstrate that equivalence in practice.

One of the more notable decisions to emerge from MSC 110 was the requirement that unmanned MASS vessels must be capable of assisting persons in distress at sea. Under the International Convention for the Safety of Life at Sea, all vessels are obligated to render assistance to those in danger. Extending this obligation to ships with no crew aboard raises complex operational questions about how an autonomous vessel would detect, approach, and aid a vessel or person in distress without human hands on deck.

The U.S. Regulatory Gap

While the IMO works toward a global framework, national regulators face their own challenges. In December 2025, the U.S. Government Accountability Office delivered testimony to Congress examining the Coast Guard’s approach to autonomous ship regulation. The GAO report (GAO-26-108762) found that the Coast Guard has received 48 requests involving autonomous ship technology since 2024, handled on a case-by-case basis through local Captains of the Port.

The report identified a structural problem: U.S. statutes establish minimum crew requirements for commercial vessels, and Coast Guard officials told the GAO they lack the authority to waive those requirements outside a narrow pilot program for at-sea rocket recovery. Industry stakeholders warned that the cost of complying with crew mandates designed for conventional ships could discourage investment in autonomous vessel development. The GAO also noted that a lack of domestic examples demonstrating autonomous ship technologies makes it difficult for the Coast Guard to evaluate the safety case for reduced or eliminated crews.

The situation contrasts with approaches taken elsewhere. Norway has approved crew reductions from five to three persons on specific vessels based on safety testing results. Canada offers exemptions from crew requirements for small autonomous vessels. The United Kingdom has modified regulations for vessels under 24 meters and issued exemptions for those under 2.5 meters. Five North Sea nations — the UK, Belgium, Denmark, the Netherlands, and Norway — signed a memorandum of understanding in 2024 to harmonize standards for autonomous vessels operating in shared waters, creating a regional framework while international rules remain pending.

Technology Outpacing Regulation

The regulatory urgency is driven in part by the pace of commercial deployment. China’s 300-TEU container feeder Zhi Fei completed what its operators described as the world’s first fully end-to-end autonomous port operation at Qingdao in February 2026, executing navigation, berthing, vacuum-based mooring, and container handling without human intervention. The vessel, which entered commercial service in 2022, has accumulated over 48,000 nautical miles and made more than one million autonomous decisions across 353 voyages.

South Korea launched its first containership designed for autonomous operations in March 2026, and Samsung Heavy Industries signed an agreement with classification society DNV to establish a remote operations center for real-time monitoring of autonomous vessels. In the United States, defense applications are driving parallel investment: Saronic closed a $1.75 billion funding round valued at $9.25 billion to scale production of unmanned surface vessels, while Blue Water Autonomy began construction of its 60-meter Liberty-class autonomous ship for the U.S. Navy at Conrad Shipyard in Louisiana.

The Gap Between Non-Mandatory and Mandatory

The six-year span between the non-mandatory code’s expected adoption in May 2026 and the mandatory code’s projected entry into force in January 2032 represents both an opportunity and a risk. The Experience-Building Phase is designed to let the industry test the framework under real conditions before it becomes binding. But critics argue that a non-mandatory code lacks enforcement teeth, and that flag states — particularly those competing for ship registrations — may apply the guidelines unevenly or not at all.

The safety acceptance study highlights another challenge: the characteristics of autonomous vessels in practical operation pose difficulties for existing regulatory frameworks, particularly around liability in the event of collisions or environmental incidents. If an autonomous vessel causes a grounding or oil spill, the question of who bears responsibility — the shipowner, the software developer, the remote operator, or the classification society that certified the system — remains largely unanswered in international maritime law.

What is clear is that the status quo is untenable. Commercial autonomous vessels are already operating on regular routes in multiple countries. The IMO’s non-mandatory code, if adopted next month, would at least establish a common vocabulary and set of expectations for an industry that has, until now, been regulated through ad hoc national exemptions and case-by-case reviews. Whether that framework proves adequate to the scale of the transformation underway is a question the Experience-Building Phase is supposed to answer — but the ships are not waiting for the regulators to finish.