IMO Adopts First-Ever Global Rules for Autonomous Ships

The International Maritime Organization has adopted the world’s first international framework governing autonomous commercial ships, marking a major milestone in shipping’s push toward remotely operated and fully autonomous vessels. 

The new non-mandatory International Code of Safety for Maritime Autonomous Surface Ships, or MASS Code, was adopted this week during the Maritime Safety Committee’s 111th session in London, according to the IMO. 

“IMO has adopted the first-ever MASS Code — a global framework for Maritime Autonomous Surface Ships,” the organization said in a social media post. “A milestone that puts IMO at the forefront of regulating emerging technologies, enabling innovation while keeping safety, accountability and the human element central to shipping.” 

The code represents years of work by the U.N. shipping regulator as autonomous technology rapidly advances across the maritime sector. Trials involving remotely operated and semi-autonomous ships are already underway in several regions, particularly on shorter routes between ports. 

Ready or Not… How Autonomous Tech is Already Quietly Disrupting Shipping

IMO first launched a regulatory scoping exercise in 2021 to determine how existing international treaties would apply to autonomous ships operating with varying levels of automation. The review spanned major conventions covering safety, navigation, training, liability, search and rescue, and port operations. 

The MASS framework defines four levels of autonomy, ranging from conventional ships with automated decision-support systems to fully autonomous vessels capable of making decisions without human involvement. 

Key unresolved issues identified during the review included defining the legal role of a ship’s “master” in autonomous operations, clarifying the responsibilities of remote operators, and addressing liability questions tied to autonomous decision-making systems. 

According to IMO documents, the MASS Code covers a wide range of operational and technical issues, including remote operations, connectivity, cybersecurity, navigation safety, machinery systems, fire protection, cargo handling, watchkeeping, and search and rescue obligations. 

The newly adopted code is initially non-mandatory, with IMO planning an “experience-building phase” beginning later this year to help regulators and industry gather operational data before final rules are developed. 

Under the revised IMO roadmap approved last year, work on a mandatory MASS Code is expected to begin in 2028, with formal adoption targeted by July 2030 and entry into force planned for January 1, 2032. 

The Maritime Safety Committee session also included discussions on shipping security in and around the Strait of Hormuz, maritime digitalization, greenhouse gas safety regulations tied to alternative fuels, and updates to safety standards covering hydrogen and ammonia-fueled vessels. 

Editorial Standards · Corrections · About gCaptain

Subscribe for Daily Maritime Insights

Sign up for gCaptain’s newsletter and never miss an update

— trusted by our 105,844 members