The SOLAS convention, under the International Maritime Organization (IMO), provides the fundamental regulatory framework for AIS. At its centerpiece lies Regulation 19 of SOLAS V (Safety of Navigation), which is specifically dedicated to AIS. Vessels on international voyages that exceed a defined size must install an AIS transponder. If ships broadcast identifiable, near-real-time data, other ships and shore authorities gain a better, faster view of traffic, which reduces the risk of collisions and helps responders in emergencies.
Ships under SOLAS oversight typically use Class A AIS, while Class B offers a practical option for smaller vessels or those not covered by SOLAS. In theory, the line of enforcement and entry thresholds can be a little hazier in practice, but the prevailing interpretation is that large vessels on international routes must carry Class A, while smaller vessels can opt for Class B if they are outside the tight SOLAS limit. The system is structured so that ships of different sizes and service types can join the same safety ecosystem without creating viewing holes.
The IMO and related regulatory bodies of this sort have issued further direction and standards codes that make true universal the idea of how AIS data should be broadcast and interpreted. This ensures that the information from a Class A unit on a freighter in one country’s waters is compatible with data received by a nearby port authority or a distant VTS center. The idea is to create a unified data environment that is interoperable and, as such, enables navigation to be safer, responses to be faster, and planning to be better across national frontiers.
Regional directives that shape AIS use in practice
In Europe, AIS sits at the core of vessel traffic monitoring and information systems (VTMIS). The European Union’s framework pushes for harmonized use of AIS data to support coastal monitoring, port operations, and cross-border traffic management. While SOLAS provides the “what,” EU rules often set the “how” in a regional context—defining how AIS feeds into national VTS centers, how data is shared among member states, and how authorities integrate AIS with other marine information systems.
In North America, national authorities align with IMO standards but layer on domestic needs. The United States uses AIS data as a central piece of its Vessel Traffic Service (VTS) and port management toolkit. Canadian jurisdictions follow a similar path in their coastal waters and major inland routes. The common thread is a mix of mandatory carriage for certain vessel types (especially those engaged in international trade or passenger service) and robust use of AIS data to support surveillance, port operations, search and rescue, and incident response.
Large shipping hubs—China, Japan, and Korea—live under SOLAS obligations just like anywhere else, and many ports require Class A AIS on international vessels. Several countries in the region have adapted rules for domestic shipping, fishing fleets, and harbor operations. Some places advocate for broader AIS adoption to enhance port efficiency and safety in places like the South China Sea and the busy straits around Singapore and Jakarta, where traffic is notoriously heavy. The practical effect is a patchwork of requirements, with core SOLAS principles guiding most international traffic and regional rules shaping domestic fleets.
Other regions—Africa, the Middle East, the Indian Ocean rim, and small island nations—follow the same core logic but with country-specific twists. In many cases, coastal states rely on the IMO framework for international ships while implementing national rules that govern domestic ferries, fishing fleets, and coastal trading. The result is a global AIS map that grows more complete every year, but still has gaps in remote areas or where enforcement resources are lean.
Regional AIS rules in practice
In European waters, VTMIS operates based on standardized data sharing, common reporting formats, and close cooperation between member states. AIS data feeds into national and regional traffic centers that coordinate vessel movements, support enforcement, and help with search-and-rescue missions. Ships operating in EU waters comply with SOLAS class A requirements for international navigation and establish procedures internally in line with EU data sharing requirements. As such, you can expect high AIS coverage in port approaches, busy shipping lanes, and crossborder corridors.
In the U.S. and Canada, AIS is now an essential safety and efficiency tool. It is a primary data source for the U.S. The U.S. Coast Guard’s Vessel Traffic Service (VTS) network tracks ship movements and coordinates responses to incidents. Carriage requirements exist for vessels that operate in U.S. waters and on international voyages. This often includes large commercial ships, passenger vessels, and other vessels that pose a higher safety risk. There are additional inland rules that push for AIS in important river systems and coastal waterways, ensuring a continuous picture of traffic from harbor entry to open sea.
The picture in the Asia-Pacific region is mixed, but it is steadily converging toward broader AIS adoption. Major ports and shipping lanes routinely rely on AIS for situational awareness. Countries with significant domestic fleets add rules that require AIS for certain ship categories, like ferries and fishing vessels, even if those ships aren’t always on international voyages. The overall effect is stronger safety and more predictable traffic patterns in some of the world’s busiest waters, along with better data to support port planning and emergency response.
Who must equip
AIS Class A is the gold standard for SOLAS ships. The system enhances position reporting frequency, data transmission quality, and operational reliability. Class A remains the default AIS choice for large merchant ships and passenger vessels, along with other vessels that operate on international routes. Since Class A is designed to adhere to SOLAS safety requirements, shipowners and operators generally consider the additional cost and complexity of installation acceptable, viewing these as direct investments in safety, compliance, and worldwide operations.
Class B provides a practical solution for smaller ships, inland vessels, and recreational craft outside the scope of SOLAS. It is less expensive and easier to install, with lesser data throughput and performance requirements. For many regional fleets and domestic trades, Class B offers a cost-effective means of achieving a basic level of situational awareness and meeting local AIS requirements, which do not necessitate the full expense of Class A. While Class B can be used in some circumstances by SOLAS-brief fleets when permitted, Class A remains the global practice for international voyages.
The choice often follows the ship’s operation profile, from a regulatory standpoint. A vessel that operates only within a country’s coastal waters or on inland waterways may be governed by national rules that favor Class B, or even no AIS at all in rare cases. For international routes, SOLAS and IMO guidelines automatically require Class A for vessels within the eligible category. Operators must verify flag state interpretation and ensure that their equipment complies with the necessary standards.