How to Use a Diving Surface Marker Buoy

Last Updated: April 27, 2023

Surface marker buoys come in all colors and sizes and are simple to use as long as you follow the instructions. These are excellent safety gear additions for any diver. Even if you do not use them regularly for marking your diving location, they are a good idea to have on hand in case of an emergency.

Here are the six simple steps to using a surface marker buoy:

  1. Determine when to release the buoy.
  2. Check your surroundings before inflating your buoy.
  3. Inflate your buoy.
  4. Let your buoy float to the surface.
  5. Ascend from your dive and keep the buoy in place until you are picked up.

diving surface marker buoy

In this article, you will learn what a surface marker buoy is, when you use one, and the different types of surface marker buoys. You will also learn how to properly deploy a SMB, how to use a delayed surface marker buoy, and how to dry them off.

What is a Surface Marker Buoy in Diving?

A surface marker buoy (or SMB) is a portable inflatable buoy usually with an attached flag that can be deployed during a dive to notify surface traffic of your presence under the water. There are different designs and also different available colors to indicate the nature of the message you want to relay to the surface.

They are typically very brightly colored in order to be distinguishable from the surrounding water. Bigger ones can be more popular to use especially in areas known for choppier waters or lacking any surrounding landmark features.

When Should You Use a Surface Marker Buoy?

Surface marker buoys can be used for a number of reasons. One of the most common uses is to indicate to motorists or boats and other divers that you are diving in the area. This is a great safety to aid avoid accidents or collisions.

They can also alert others to your whereabouts. If you get lost from your group, especially if you’re diving in open water, it can help your group pinpoint your location. If you’re drift diving or drift snorkeling, having a surface marker buoy is essential for the boaters to locate where to pick you up when you’re done.

Some divers use it to help them ascend in a controlled manner or if they are diving in an area with a strong down current. The final reason for using a SMB is to indicate an emergency situation. They can be color coded according to the nature of the emergency so that surface support can respond appropriately.

Types of Surface Marker Buoys

Although there are many different brands that offer various options for colors, sizes, and designs, there are three main categories of surface marker buoys:

  • open end
  • closed end
  • and delayed

Open end surface marker buoys have an open end that remains underwater while at the surface in order to stop air from escaping and the tube from deflating. These buoys are best to use when surface winds and waters are calm and predictable.

Closed end surface marker buoys are completely enclosed float tubes with an inlet valve to prevent air from getting out. These are best to use in rough choppy waters and are usually designed in brighter colors for easy sight recognition.

Delayed surface marker buoys are those that are inflated and released underwater. These are most commonly used for emergency situations or if divers get separated from their group.

How to Deploy a Surface Marker Buoy (SMB)

A surface marker buoy can be deployed prior to diving if a diver is drift diving and the boat needs to track the location of the diver as he rides the current.

Be sure to check your surroundings first before deploying the line so that you don’t entangle it in someone else’s gear.

Allow yourself an ample amount of line to be able to dive with so that you are not kept at the surface.

Deploy the buoy by inflating it with air from your mouth or your BCD. For underwater deployment, ensure that it does not cause you to ascend in a rapid uncontrolled manner.

How to Use a Delayed Surface Marker Buoy

A delayed surface marker buoy (DSMB) is one that is deployed while still underwater for various reasons, either due to an emergency or simply signaling the boat to pick you up.

If possible, ascend to your safety stop at 5 meters and make sure you are neutrally buoyant.

Allow a little bit of air from your regulator to fill the bottom of your buoy so that it stands up.

Unlock your reel line and make sure it is not wrapped around your fingers. Hold it out in front of you to ensure it does not get tangled up in your gear.

Fill the SMB with your alternate air source and allow it to float to the surface once it is filled. When it hits the surface, pull a little on the line to make sure it is taut so that the buoy is standing up and visible to any surface traffic.

Continue your planned ascent and leave your buoy inflated until you are picked up by your boat.

How Do You Dry a SMB?

Just like any other piece of dive equipment, your surface marker buoy should be rinsed off with fresh water after every dive. Allow it to air dry, preferably outside in the shade. You do not want to leave it in the sunlight as this might cause the colors to fade and those need to be bright in order to signal necessary surface traffic.


Surface marker buoys have become a necessary piece of safety equipment for scuba divers that can help prevent accidents, alert surface parties to underwater emergencies, as well as help pinpoint the location of divers in need of pickup.

There are many different kinds and colors depending on the nature of the dive. Delayed surface marker buoys are particularly useful for divers to indicate when and where they need to be retrieved from the water.

The important safety tips to remember when using a surface marker buoy are to avoid entanglement in the line and make sure the buoy does not cause an uncontrolled ascent.

Always make sure to take proper care of your gear, including your SMB, after a dive.

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