3 Best Surface Marker Buoys (dSMBs Tested by Divemaster)

Written and Reviewed By

Diver in a pool showing how to inflate an SMB underwater

An SMB, or surface marker buoy, is a boat diving accessory that no responsible scuba diver should ever dive without.

As a PADI Divemaster working in the South Florida scuba diving industry, I don’t get surprised anymore when new, and even some experienced divers, neglect an SMB as part of their dive loadout.

While any respectable boat diving operation SHOULD have SMBs on board for its divers, you should not rely on them to have one.

Surface marker buoys are not expensive, and they’re small and light enough to bring when you travel.

So there’s really isn’t a reason to not get your own SMB!

That being said, there are so many different SMBs out there, it can be hard to know which one to buy.

That’s why I put together a list on the three best surface market buoys on the market, along with who each one is best for, allowing you to easily pick the best one for you.

I picked and graded SMBs based on the following qualities:

  • Visibility
  • Length & shape
  • Price
  • Inflation methods
  • Attachment points
  • Type of valve
  • Material
  • Reels
  • Manufacturer repuation
  • & more

After reviewing each SMB, I’ll share my SMB buying guide and answer some FAQs, followed by tips on how to deploy an SMB and DSMB.

Let’s get started.

Table of Contents

Best SMBs for Scuba Diving

Our Top Pick

DiveSafe Delayed SMB - 6ft Open Bottom

  • Large & highly visible
  • 3 different colors available
  • Compact all in one DSMB kit
  • Durable & long-lasting
  • 2 different inflation methods
  • Reflective strip & dump valve
  • It’s a little pricey
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03/09/2024 12:46 am GMT

Offering everything you need in one compact yet robust package, the Dive Smart 6ft open-ended SMB our favorite pick on the list.

Made from 210D Nylon with a TPU coating, this SMB is built to last. The Dive Smart SMB features an overpressure valve and weighted bottom, ideal for all dive conditions.

This SMB is easily inflated using either oral inflation or a regulator second stage. The open-end has a one-way airflow system that prevents any air from escaping at the surface. Available in 3 different high visibility colors, all featuring a large reflective band at the top.

What’s more, this SMB comes with a 100ft (30m) reel, double-ended brass clip and it’s own mesh pouch with a velcro locking system.

Product Specs:

  • Reel/Line type: 100ft dive spool
  • Length: 6ft
  • Colors/Visibility: 3 colors & 500 yards
  • Attachment Points: Double ended clip
  • Valve: Open bottom 
  • Material: 210D Nylon Fabric
Budget Option

Seafard 4ft Open Bottom SMB

  • High visibility design
  • Comes with reel & clip
  • Compact & lightweight
  • 2 different inflation methods
  • A little too small for rough sea conditions
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03/09/2024 04:05 am GMT

The Seafard SMB is another great choice. Although slightly smaller than the Dive Smart, this SMB is highly visible and extremely robust. It’s lightweight and compact design makes the Seafard SMB an ideal choice for the traveling diver.

Featuring an oral inflation tube, self-sealing open bottom, dump valve and reflective strip, this SMB has everything you need.

Plus this SMB also comes with a corrosion-resistant aluminum reel with 49ft of braided nylon line and a stainless steel double-ended bolt clip.

Product Specs:

  • Reel/Line type:49ft of braided nylon line
  • Length: 4ft
  • Colors/Visibility: 3 colors 
  • Attachment Points: Double ended clip
  • Valve: Closed valve
  • Material: 210D Nylon Fabric
Best Dive Buoy

DiveSafe Scuba Round Buoy Float

  • Great value
  • Permanent visibility at the surface
  • Robust & long lasting
  • Cannot be used as a DSMB
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03/09/2024 06:21 am GMT

The DiveSmart dive float is the ideal surface marker buoy for both scuba diving and free diving in areas with high boat traffic.

This SMB is easy to set up and provides permanent visibility at the surface. Plus it comes with a 100ft reel and double-ended clip.

Product Specs:

  • Reel/Line type: 100ft high visibility finger spool
  • Length: 13′ diameter
  • Colors/Visibility: Red & white
  • Attachment Points:Double ended clip
  • Valve: Closed valve
  • Material: Nylon

But Do I Really Need My Own SMB?

So you might be thinking…

‘The dive guide always has an SMB, so I don’t need my own’

While it’s true that your divemaster or guide should always carry an SMB with them, it’s still highly recommended that you have your own surface marker buoy.

And here’s why…

Having your own SMB means you can always take care of your own safety.

Scuba Diver ready to inflate their SMB underwater

Perhaps you and your dive buddy want to explore an area away from the main group. There are many dive destinations and liveaboards that allow more experienced divers to dive without a guide. Having your own SMB provides you with much more freedom underwater.

But even if you’re not planning to venture away from your guide there are still situations where you may need an SMB. And where not having one could easily turn a common situation into an emergency.

For example, what happens if you lose your dive guide and have to ascend without them?

Losing your guide is not necessarily an emergency in itself. But without an SMB you have no way of alerting boat traffic as you ascend, or attracting attention at the surface. Both of which could result in an accident.

And even if your dive buddy always carries an SMB. What happens if you lose your buddy and the group?

An SMB is vital if you have to ascend by yourself. Ultimately, this is the reason why every scuba diver should have their own SMB.

Some divers may argue that in this situation they can use their alternate air source to blow bubbles to mark the surface. But seriously, have you tried spotting a divers’ bubbles in choppy conditions?

upwards perspective of fish and bubbles while underwater

An experienced captain might be able to. But often it’s impossible. And other marine traffic will definitely not be able to see you.

What’s more, many dive operators and liveaboards now require all divers to have their own SMB.

An SMB is a very small and relatively inexpensive addition to your dive gear. Yet it massively enhances your safety. So why take the risk?

Why Do You Need An SMB?

This is the most common question when it comes to surface marker buoys. Here are the reasons why you most certainly need an SMB for scuba diving:

Mark Your Ascent Point

This alerts any boats in the area that there are divers just below the surface so they can maintain a safe distance. Ascending without an SMB puts you at risk of being injured by passing boat traffic.

Extra Visibility

This ensures that your dive boat can find and helps you to attract attention if you’re lost at sea or an accident happens. It’s much easier to spot a big, bright SMB on the surface than a divers wet head, especially in bad weather.

Emergency Flotation Device

If the boat is not in sight and you have to wait a long time at the surface, an SMB can provide additional support and a great sense of security.

Safety Stop Visual

When drift diving, it’s not uncommon to have to complete your safety stop in the blue. Here, a DSMB helps you maintain a steady depth and allows the boat to follow your movement. What’s more, the line of the DSMB provides a handy visual reference, ensuring a slow and steady ascent.

How To Choose The Best SMB For Scuba Diving

MBs come in a wide variety of brands, shapes, and sizes. The best SMB for you will depend slightly on your personal preference but ultimately it comes down to the dive environment.

So let’s take a bit of a closer look at the different types of SMBs and what to consider when choosing an SMB for scuba diving.

Open-Ended Vs Closed-Ended SMBs

There are two main types of SMBs for scuba diving; open-ended and closed-ended.

An open-ended SMB is open at the bottom. These SMBs can be inflated using your exhalations or your alternate air source.

Open-ended SMBs are very easy to inflate and deflate. However, air tends to escape from the bottom so they often flop over at the surface making them less visible. You can reduce this by pulling down on the line to hold them upright, although some water will still get inside.

Photo example of an open ended SMB

The best open-ended SMBs will feature a one-way airflow system. This means that when the SMB is inflated the opening is pinched closed by the air pressure inside. These SMBs are easy to inflate and will always maintain their position on the surface.

Photo example of a close-ended SMB

Close-ended SMBs are completely sealed all the way around. A close-ended SMB is usually inflated by blowing into a one-way oral inflation tube, although some models can be connected to a low-pressure inflator hose to add air more quickly.

Closed SMBs will always sit upright at the surface but tend to be a little trickier to deploy, especially underwater.

Whichever type of SMB you choose, make sure that it features a dump valve. As the SMB shoots up to the surface the air inside will expand due to the pressure change. A dump valve will allow any excess air to escape, preventing the SMB from bursting.

Shape, Color & Size

Permanent SMBs are often round, but if you’re looking for a DSMB you want to pick a long, tube shape that will stand tall on the surface. These SMBs can also be easily rolled up and clipped to your gear.

When it comes to color, it’s vital that your SMB stands out against the water. So make sure you choose a brightly colored SMB. Orange or red provides the highest contrast, but fluorescent pink or yellow will also work well.

Having a reflective strip at the top of your SMB is also very useful. This makes you much easier to spot especially in poor visibility or low light.

With regards to size, your SMB should be at least 3ft (or 1m) in length. But as with many things in life, the bigger the better!

If you’re diving in relatively calm waters with little to no current then a smaller SMB will suffice. However, if there is any chance of waves or currents it’s important to have a large SMB that can easily be spotted even in rough conditions.

photo example of an SMB with reflective strip for safety

SMB Attachments & Accessories

All SMBs require some sort of line so that it doesn’t just drift away at the surface. Some SMBs will come with a 5 – 6m wrapped line, which is just long enough for your safety stop.

However, wrapped lines are very prone to tangling and don’t offer you the opportunity to deploy the SMB from deeper depths if needed. Plus if there are any waves, wind, or current the line will be pulled which means that 5m won’t be long enough.

65ft SMB finger reel attachment on white background

Most divers prefer to use a reel with their SMB. A reel safely stores the line and greatly reduces the risk of entanglement. A reel with a 65ft (20m) line is recommended for most recreational divers. But you may want to get a longer line for drift or deep diving.

Reels come in many different forms, but remember the simpler the mechanism the less there is to go wrong. A mounted hand reel is recommended if you’re diving in a location with particularly strong currents or challenging surface conditions. However, for most dive locations, a basic finger reel will work well enough.

SMB reel attachment with handle on white background

With a reel, you can deploy your SMB from deeper depths. Not only is this easier as you don’t need to add as much air, but it can also be very useful in alerting boats to your position before you ascend to your safety stop. The line can also be used as a visual reference to guide a slow and steady ascent.

A double-ended clip is used for attaching the DSMB to your gear and preventing the line from unraveling.

How To Deploy An SMB

The method for inflating an SMB at the surface will differ slightly depending on the type of SMB you are using.

How To Inflate An SMB At The Surface:

  1. Place the mouthpiece of your alternate air source just inside the open end of the SMB.
  2. Turn the alternate air source upside down and pull the open end of the SMB slightly under the surface.
  3. Push the purge button on the alternate air source whilst holding the open end of the SMB until it is full.
  4. Pull the end of SMB down slightly in the water to make it stand tall.

To inflate a close-ended SMB simply blow into the oral inflation tube.

How To Inflate An SMB Underwater:

Every diver will have a slightly different method, but here are the general steps for deploying a DSMB:

  1. Make sure that you are neutrally buoyant at around 5m or deeper and check there are no obstructions above or around you.
  2. Unclip the SMB from your BCD and open it out.
  3. Optional: Add a tiny amount of air into the SMB so it sits upright. (Use a small tap from your alternate air source or bring the opening of the SMB to the exhaust of your regulator, tilt your head to the side and exhale)
  4. Unclip the SMB from the reel and store the clip on your BCD.
  5. Hold the reel so that it can freely spin on an axis created by your finger, or finger and thumb.
  6. Make sure the line is on the outside of the reel facing away from you and not wrapped around any of your gear.
  7. Inflate the SMB using 2-3 full exhales or a short blast from your alternate air source
  8. Let go of the SMB and allow the reel to spin. Remember to watch your dive computer to maintain your depth.
  9. Once the SMB is at the surface you can wind the line tight around the reel and hold onto the reel until your safety stop is finished.
  10. Wind the line around the reel as you ascend slowly.

For a close-ended SMB, you would remove your regulator and exhale into the inflation tube. Don’t forget to save a little air to clear your regulator afterward and never hold your breath!

Sounds like a lot to think about? That’s because it is.

Deploying a DSMB correctly will take a few attempts. But once you’ve mastered it you’ll feel much safer and more independent underwater.

We highly recommend you practice in a swimming pool or very shallow water first to avoid the dangers of a rapid ascent.

And if possible, have a dive instructor teach you how to safely inflate an SMB underwater.

Diver in a pool showing how to inflate an SMB underwater

Top Tips For Deploying An SMB Underwater


This helps counteract the positive buoyancy created by the air you add to the SMB. Try exhaling as you inflate the SMB or deflate your BCD slightly before inflating the SMB.


Make sure that the SMB and reel are set up properly before you add any air. If you rush it’s much more likely that you will get tangled in the line.


Remember to allow the reel to freely spin and don’t be afraid to let go of the reel if it gets stuck or is pulling you up.

Many divers will instinctively grip hard on the reel and end up being dragged to the surface. It’s much easier and safer to just let it go. The reel will almost always fall back down to you.


If the SMB is accidentally caught by a boat you’ll be pulled up very fast which can lead to decompression illness and other injuries.

Frequently Asked Questions

Q: What is an SMB?

SMB stands for surface marker buoy. An SMB is a simple inflatable device that floats on the surface to mark the position of scuba divers. This allows people at the surface to keep track of the divers and lets boats know to stay away.

Typically a surface marker buoy is inflated at the beginning of the dive and towed along by the diver. An SMB can also be inflated at the end of the dive to signal the dive boat to come to pick up the divers.

SMBs can be round or a long tube shape. They are always brightly colored making them easy to spot, even in rough conditions.

Q: What is a DSMB?

A DSMB, or delayed surface marker buoy, is a type of surface marker buoy that divers inflate underwater and release to the surface prior to ascending. Hence the term ‘delayed’. You may also hear divers fondly refer to their DSMB as a safety sausage due to its long, round shape.

Q. Does every SMB include a clip and reel?

Not every SMB comes with a clip and reel some are sold separately. Some of the more expensive SMB’s will have a clip and reel included.

Q. Are all SMB's the same size?

Not all SMB’s are the same size, they typically range from around 4 – 6 feet. There are options to also get smaller and taller size SMB’s. If you are diving in rougher waters with bigger waves, you may want to get a larger SMB.

You can get different size SMB’s depending on the conditions you’re diving in and personal preferences. We recommend that your SMB is at least 3ft (1 meter) in length, but if you are diving in rougher conditions then a larger SMB is recommended.

Q. Are SMB's all the same color?

SMB’s vary in color and most of the time are down to personal preference. They are always bright and stand out from the ocean. The most popular colors are yellow, orange and pink.

Q. Can you rent an SMB?

Most dive shops will have SMB’s available for you to either rent or use as part of a course. But having an SMB that you are familiar with can help you become confident in how to deploy an SMB successfully.


So now you understand why an SMB is an essential piece of scuba diving gear. And how to choose the best SMB for your scuba diving adventures.

No matter which surface marker buoy you choose, we guarantee that you’ll feel much safer and more independent with your own SMB.

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