If you’ve been shopping for an AIS Man Overboard (MOB) beacon recently, you’ve probably seen references to Class M. If you’re like many boaters and water lovers, the term might bring up a lot of questions and some confusion. You might be asking: Do existing MOB devices still work? Is this only a European regulation? Why have regulators announced an entirely new standard? What does this mean for me? The Class M Regulation represents one of the biggest changes to personal maritime safety equipment in years. We hope this article provides some clarity and helps you better understand Class M.

What is Class M? Is it replacing AIS?

Let’s first get clear on what Class M is not. One of the big misconceptions is that Class M is replacing AIS. It’s not. Rather than replacing AIS, Class M is teaming up with it because AIS alone isn’t always enough.

Traditional AIS MOB devices transmit coordinates over AIS, allowing nearby vessels to see the MOB on their chart plotters. This system relies on someone actively watching their display. If nobody notices the symbol immediately—or if the bridge is busy—valuable rescue time can be lost.

Class M introduces another layer of protection. Rather than relying solely on an AIS transmission appearing on nearby chart plotters, Class M devices also transmit an audible Digital Selective Calling (DSC) distress alert that notifies vessels within VHF range. This audible alert significantly increases the chances that someone notices a distress call immediately. Moreover, the DSC acknowledgement feature gives the MOB peace of mind that their rescue alert has been received.

Simply put, Class M improves how personal man overboard devices communicate during an emergency, facilitating a faster response.

How did the Class M Regulation evolve?

Class M stems from ECC Decision (22)02, developed by the European Conference of Postal and Telecommunications Administrations (CEPT). Its purpose is to improve the effectiveness of AIS channels while making man overboard alerts more reliable. The CEPT regulators noticed that AIS channels were becoming increasingly busy with a growing number of Autonomous Maritime Radio Devices (AMRDs), including fishing net markers, navigation buoys and other transmitters. Due to these crowded channels, regulators became concerned that non-vessel devices could impact the visibility and reduce the effectiveness of AIS distress calls.

CEPT and Class M addressed this by separating different device types and requiring modern MOB beacons to use both AIS and DSC, as explained above.

How does this affect me?

That depends on where you sail. For now, Class M does not apply outside of European countries, so if you’re in the United States or another region, there is no regulatory change. Even within Europe, Class M is not automatically law everywhere.

The ECC decision allows each CEPT member country to adopt the regulation individually. Some countries have already implemented it, while others remain in consultation or planning phases. Boat owners should check the requirements in the countries where they operate rather than assuming the same rules apply everywhere. You can check Class M status among European CEPT countries here.

Where Class M has been adopted, older AIS-only MOB devices may no longer be compliant for licensing or use unless they operate under the revised channel arrangements. That doesn’t necessarily mean they stop functioning—but compliance requirements are changing and it’s worth taking note.

For anyone purchasing new equipment today, choosing a Class M-compliant device is generally the most future-proof option. MRT recommends a device that includes AIS transmission, integrated GNSS positioning, DSC distress transmission, and DSC acknowledgement capability. The sMRT ALERT AIS MOB device is a great example of a modern Class M device.

Compliance is only the beginning

Meeting the regulation is important but compliance alone doesn’t guarantee the fastest rescue. A successful MOB recovery depends on the entire alerting ecosystem—from the beacon itself to onboard receivers, crew response and situational awareness. That’s why many marine safety professionals are looking beyond minimum compliance toward integrated rescue technologies that form a complete recovery system that locates, reaches, and retrieves.

Look out for our next article in the Class M series and contact us with any questions about meeting the regulation and updating your equipment. We’re here to help.