Dana S. Merkel, Alan M. Weigel, and Vanessa C. DiDomenico ●
The International Maritime Organization (“IMO”) formally adopted the International Code of Safety for Maritime Autonomous Surface Ships (“MASS Code” or the “Code”) on May 22, 2026, marking a significant regulatory milestone for autonomous shipping. Adopted at the conclusion of the 111th session of the Maritime Safety Committee (MSC 111), the Code establishes a goal-based framework to govern the design and operation of remotely controlled and fully autonomous commercial vessels. The Code took effect on July 1, 2026.
The U.S. Coast Guard (“USCG”) also released guidance with respect to remotely controlled and autonomous vessels recently. Issued in the form of a Work Instruction, the policy provides guidance to USCG units and industry on approval and oversight of unmanned vessels.
An International Framework Built on Safety, Security, and Environmental Protection
The MASS Code sets out to ensure that remotely operated and autonomous vessels meet the same standards of safety, security, and environmental protection expected of conventional vessels. Ships falling under the Code must also comply with the International Convention for the Safety of Life at Sea (“SOLAS”) and other applicable mandatory IMO instruments. In its current form, the Code applies exclusively to cargo ships and, at this stage, is non-mandatory, giving IMO Member States the opportunity to test its application while laying the groundwork for a future binding instrument.
The Code introduces new requirements across several critical domains, including navigation, connectivity, remote operations, fire safety, and search and rescue. It places strong emphasis on risk assessment, robust system design, cybersecurity, and the integration of Remote Operations Centers (“ROCs”), the land-based facilities from which some or all operational aspects of a MASS may be managed. Importantly, the Code is designed as a goal-based, technology-neutral instrument, meaning it complements existing IMO instruments and focuses on areas not adequately addressed by the current regulatory framework, without prescribing specific technologies.
One of the Code’s most significant provisions is its treatment of the human element. The MASS Code requires that a human master remain responsible for the ship at all times. While the master may not always be physically on board, depending on the technology employed and the degree of autonomy, that individual must retain the ability to intervene when necessary. This principle ensures that human oversight remains a cornerstone of autonomous shipping, even as the industry moves toward higher levels of automation.
Although the adoption of the non-mandatory MASS Code is a notable achievement, it is deliberately the first step in a phased approach. According to the roadmap agreed upon at MSC 109, the IMO will develop a framework for an Experience-Building Phase (“EBP”) following the Code’s adoption, with that framework expected to be established by December 2026. The EBP is designed to allow industry participants and Member States to apply the Code in practice, gather operational data, and identify any gaps or areas requiring refinement.
According to the IMO[1], development of the mandatory MASS Code is scheduled to commence in 2028, drawing on the non-mandatory Code and the findings of the EBP. This mandatory instrument will also require amendments to SOLAS, potentially through a new chapter, to give it binding legal force. The IMO’s target is to adopt the mandatory Code by July 1, 2030, with entry into force on January 1, 2032.
Domestic Guidance
The USCG issued Work Instruction 5P-WI-002(1), Oversight of Unmanned, Autonomous and Remote-Control Operations[2](Work Instruction), on June 1, 2026, providing risk-based guidance to District Commanders; Captains of the Port (“COTP”); and Officers in Charge, Marine Inspection (“OCMI”) evaluating operations involving unmanned, autonomous, or remote-controlled maritime technologies. The instruction covers uninspected Unmanned Maritime Systems (“UMS”) (not subject to Coast Guard inspection and not carrying passengers for hire), uninspected passenger vessels, and inspected vessels.
The Work Instruction states that owners and operators of all UMS should provide advanced notice of UMS activities to the cognizant COTP and should also be prepared to discuss the following details with the COTP: point of contact information; operational details, including vessel characteristics, dimensions, speed, propulsion type, purpose, and description of activities; operating location and schedule; onboard systems and sensors; control modes; operator procedures; emergency management and response procedures; cybersecurity measures; and operator training and qualifications; and have a Convention on the International Regulations for Preventing Collisions at Sea, 1972 (“COLREGS”) compliance statement, explaining how the UMS and operator will comply with COLREGS, especially for lookout, maneuverability, navigation and lighting. For inspected vessels, OCMI will evaluate the proposals to ensure compliance with applicable regulations and will forward the proposal with an initial recommendation to the Commandant via the applicable District, who will then provide a recommendation back to the OCMI. The OCMI retains final authority for the approval or disapproval of the request.
The Work Instruction specifically states that the OCMI shall not establish manning that is less than the minimums in 46 U.S.C. 8301 and 46 C.F.R. Part 15 and notes that COLREGS require that a vessel shall, at all times, maintain a proper look-out by sight and hearing.
While the Work Instruction expressly does not implement the MASS Code, the USCG acknowledges it as a meaningful step toward integrating autonomous vessels internationally and notes that its own priorities: safe navigation, human oversight, cybersecurity, and accountability, align with the Code’s goal-based approach.
Industry and Legal Implications
The MASS Code arrives at a time of rapid technological advancement in the maritime sector. Several countries have already developed or are constructing MASS prototypes for commercial application and training purposes, and autonomous vessel technology is transitioning from concept to practical application at an accelerating pace. The Code provides critical regulatory clarity for technology developers, operators, and investors, who have long cited the absence of clear international requirements as a primary obstacle to commercialization.
From a legal perspective, the Code raises important questions around liability, insurance, and the alignment of national regulatory frameworks with the emerging international standard. The IMO’s Legal Committee has examined the implications of autonomous shipping for existing liability and compensation treaties, concluding that while MASS can largely be accommodated within the current framework, certain concepts such as “fault,” “negligence,” and “intention” require reconsideration in the context of harm caused by autonomous technology.
Notably, the Comité Maritime International (“CMI”) has been working with the IMO on issues relating to MASS since 2017 when the CMI established an International Working Group on MASS (“IWG/MASS”) to study the current international legal framework and consider what changes may be required in relation to unmanned ships.[3] The analysis considered the applicability of these regulations to MASS and the ability of such ships to comply with them. It also considered how the relevant level of autonomy might impact the regulation. The IWG/MASS also has studied the issues that arise from introduction of autonomous technology and possible strategies for resolution. Some of the questions considered by the IWG/MASS include: whether modification may be required in light of the legal issues MASS raises under the current maritime liability regime; the legal status of the ROC of a remotely operated MASS; the ability of a MASS to provide assistance to persons in distress at sea; and how the traditional functions and roles of a ship’s Master can be performed in a MASS context.
Conclusion
There is still work to be done in the development and regulation of new ships and systems to respond to unique conditions aboard an unmanned environment. The MASS Code and USCG Work Instruction domestically, provide the indispensable first chapter: a foundation upon which a mandatory framework, with technical specificity, and the commercial future of autonomous vessels will be built.
This article is one in a series of articles written for Blank Rome’s MAINBRACE: August 2026 edition.
[1] IMO, Autonomous Shipping, Available at: imo.org/en/mediacentre/hottopics/pages/autonomous-shipping.aspx .
[2] U.S. Coast Guard, Work Instruction 5P-WI-002(1), Oversight of Unmanned, Autonomous and Remote-Control Operations, available at: dco.uscg.mil/Portals/9/DCO%20Documents/5p/CG-5PC/CG-CVC/CVC_MMS/5P-WI-002(1)%20Oversight%20of%20Unmanned%20Autonomous%20and%20Remote-Control%20Operations-Final.pdf.