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What Is A Surface Marker Buoy (SMB) & What Is It Used For?

   December 13th, 2023   Posted In: Articles   Tags:

When you’re diving into the depths of the underwater world, dive safety and communication are imperative tools you will need for a successful water adventure. Another essential tool for divers is the Surface Marker Buoy (SMB). In this helpful guide, we’ll explore what a diving buoy is, what it’s used for, why it’s crucial, and the two main types of surface marker buoys.

What is a Diving Buoy?

Let’s start with the basics. What is a diving buoy? Simply put, it’s a buoyant device used by divers to signal their location to those above the surface. Think of it as your underwater flag – a bright, floating indicator that lets the world know where you are.

The Surface Marker Buoy (SMB): A Diver’s Beacon of Visibility

Now, within the realm of diving buoys, the Surface Marker Buoy (SMB) takes center stage. An SMB is a buoyant tube, often brightly colored, with an attached line. They come in multiple colors and forms. Divers deploy it during their ascent to signal their presence to boat operators, fellow divers, or anyone else on the surface.

What Is a Surface Marker Buoy Used For?

An SMB is used for multiple reasons including:

Visibility & Safety

The primary purpose of an SMB is to enhance the visibility of a diver during ascent. As divers make their way back to the surface, the buoy marks their location, reducing the risk of collisions with boats or other watercraft.


Beyond visibility, an SMB is a diver’s silent communicator. It’s not just a marker but a message – a way to alert those on the surface about the diver’s location and impending ascent.

Current Management

In strong currents, maintaining a steady ascent can be challenging. The line attached to the SMB provides a stable reference point for divers, allowing them to control their ascent and safety stop more effectively.

Why is it Important?

Diving buoys are more than just fun or bright colored floats. Learn more below.

  1. Safety First: The underwater world is a beautiful but challenging environment. Diving buoys play a vital role in diver safety by reducing the risk of accidents and ensuring that boats can steer clear of ascending divers.
  2. Emergency Signaling: In case of an emergency, the SMB can be used as a distress signal. By rapidly inflating and deflating the buoy, divers can communicate urgency to those on the surface.
  3. Peace of Mind: Knowing that there’s a visible marker above you provides a sense of security. It allows divers to focus on the joy of exploration, confident that their presence is well-noted by those on the surface.

The Two Types of Surface Marker Buoys for Diving

Now that you’re acquainted with what an SMB is and why it matters for divers, here are the most common types of SMBs for diving:

Inflatable SMBs

The classic choice, inflatable SMBs are compact and easy to carry. Divers can inflate them using their regulator or an oral inflation valve. Once deployed, these buoys stand tall, making them highly visible on the water’s surface.


  • Portable and lightweight.
  • Easy to deploy and deflate.
  • Excellent visibility.


  • Requires manual inflation.
  • Sensitive to wind.

Self-Inflating SMBs

As the name suggests, these SMBs take care of inflation automatically. Fitted with a CO2 cartridge, they inflate rapidly when triggered. This type is favored for its speed and convenience.


  • Rapid inflation.
  • Ideal for emergency situations.
  • Less effort required.


  • Heavier than inflatable SMBs.
  • CO2 cartridges need periodic replacement.

Choosing the Right SMB for You: A Quick Wrap-up

Whether you opt for the classic inflatable SMB or the convenient self-inflating version, having a Surface Marker Buoy in your diving arsenal is a non-negotiable. It’s not just about complying with safety standards; it’s about ensuring a seamless and secure underwater experience.

So, the next time you gear up for a dive, don’t forget to pack your SMB – your silent companion in the vast, mysterious depths. Happy diving!

Lauren (LoLo) has been turning words into blog posts for Wetsuit Wearhouse since 2014. She learned to surf for the first time ever in Costa Rica but she gravitates more towards SUP. When she's not scouring the web for travel deals, you can find her either hiking, running, gardening, tending to her animals, or reading a good book outside on a beautiful day.

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