What Kind of Surface Marker Buoy Should a Diver Get?

Every scuba diver needs safety equipment, no matter how experienced or well-trained they are. One piece of safety equipment they need is surface marker buoys. These brightly-coloured inflatable devices effortlessly float on the water and warn anyone who needs to see them. They keep the scuba divers safe and are most helpful in diving spots with heavy boat traffic. 

The Two Kinds of Surface Marker Buoy

You might come across two types of surface markers. Both types aim to inform people on the surface about where you are positioned. 

One is the surface marker buoy (SMB). It is round and uses bright red, yellow, or orange colours. It is left at the surface area where the team plans to dive. This buoy is usually sealed to help keep them in place and stop possible deflating while the unit is on a dive. Some SMBs have text and attached flags in them for higher visibility.

Meanwhile, the sausage-shaped buoy or the delayed surface marker buoy (DSMB) is the buoy carried by the diver and inflates only when needed. Divers usually use it to communicate to the boat when they plan to resurface. It shows that the diving team has reached the end of their session, and they are about to resurface to wherever the buoy reveals itself. 

Considerations When Buying a Buoy

Before buying the buoy you need, here are some of the other considerations you need to also think about:

  • What Size and Colour?

Buoys come in different sizes, shapes, and colours. The answer to this question usually depends on where the team plans to dive. The larger buoys are best suited for areas with bigger waves. In terms of colour, the best one to use should be the strongest contrast against sea colours. The standard colours are red and orange, while yellow signifies an emergency. 

  • What Kind of Bottom to Get: Open or Closed?

Two kinds of DSMBs also exist—the open-ended and the closed DSMBs. From its name, the difference between the two is how the former is not completely sealed at the bottom while the latter is the sealed version. 

The unsealed or open-ended version is the easier one to inflate, especially when underwater. At the same time, even when outside of the water, it is easier to deflate and store. Its only downside is the high possibility that water will enter it once it reaches the surface of the ocean. 

When this happens, the buoy can flop into a horizontal position, making it a little harder to see and keep upright. The trick is to tug it a little as it floats to control its position. However, there is no guarantee that it would not shift upon reaching the surface. 

On the other hand, the sealed version is harder to inflate, but they stick upright in the water, making it highly visible on the surface. The only catch is that there is only one way to inflate it.

  • How Do You Want to Inflate It?

The open and closed DSMBs vary in the way they are inflated. The open DSMB usually requires air from a diver. That means they need to take off their regulator and take a breath to fill it from the bottom. As it ascends to the surface, the air would naturally expand to fill the space completely. 

Closed DMBs can also follow the same method for inflating, but it also has an alternative. The other being using the LPI (low-pressure inflator) device to add more air. For this reason, the buoy would be fuller upon reaching the surface. This option is the best for those who do not want to remove their mouthpiece while underwater. 


Every professional diver knows the importance of bringing life-saving equipment during their dives. But before you get yourself one, make sure that you use the correct item to communicate the right message. This article has provided the difference between the two surface marker buoys available for purchase. As a diver, it would be best to have both to cover for their different purposes. 

Are you wondering where you can buy marker buoys in Australia? Purchase one from Swim Secure. We are the market-leading supplier of open water dry-bags, tow-floats, including surface marker buoys, and more. We provide swimmers, recreational swimmers, triathletes, and divers the protection they need.