A diver will always need to carry a dive knife when diving. A dive knife will help you or a marine animal get out of an emergency situation. Dive knives can quickly go from a handy tool to a lifesaving tool in just a matter of seconds, which is why you should always carry a dive knife when diving.

There are many styles, sizes, and shapes of dive knives today. It can be difficult to decide which one is the best, and that’s exactly what we have come to discuss today.

We have compiled a list of the best dive knives along with some helpful information that will make your dive knife decision the easiest one yet.

Promate Scuba Diving 5” Stainless Steel Knife

This dive knife by Promate has a 5” 304-grade stainless steel blade with a total length of 10.5 inches from blade tip to the butt of the handle. The blade is serrated on one side and plain on the other, which makes it perfect for cutting any type of material while diving.

The knife comes with a sheath, adjustable straps, and a lanyard hole. This makes storing and carrying the knife easy, especially while diving when impacts and sudden movements can easily shake the knife loose if it is not properly secured.

Any knife that will enter saltwater will have to be well taken care of, so it should be dried immediately when removed from the water. Adding mineral oil to the knife blade will also help the blade stay clean and rust-free.


● Easily secured, adjustable sheath straps, and a lanyard hole in the design
● Serrated and plain blade
● Not too big or too small
● Comfortable grip


● Quick to rust; needs routine maintenance after each submersion

Cressi Borg Long Blade Diving Knife

The Cressi Borg long blade diving knife is a total length of 10.43 inches with a knife blade of 5.51 inches. The knife blade is serrated on one side and plain on the other, making it versatile for cutting many different types of material.

The grip of the blade is made of hard rubber and has a comfortable ergonomic design. It sits comfortably in the hand and contours naturally with the grip of the hand.

Included with the knife are a sheath and two standard-issue straps. The sheath has a locking mechanism that can be unlocked to remove the knife with one hand. The straps are rubber and can be strapped to your leg. The rubber straps keep the knife sheath in place securely while diving.


● Comfortable grip
● Stays securely in place with rubber straps
● Sharp blade; serrated on one side and straight on the other


● The locking mechanism can malfunction after saltwater and sand exposure

Bahia Dive Supply Stainless Steel Dive Knife

Bahia Dive Supply Stainless Steel Dive Knife

$22.87 Amazon 

The Bahia Dive Supply stainless steel knife has three types of blades in one: a straight edge, a serrated edge, and a line cutter. This means you can cut all types of materials using just one knife. The blade is made out of 420-grade stainless steel, which will keep it free from rust and corrosion.

The sheath has a quick-release clip that allows you to remove the knife with just one hand. The sheath can be strapped to the leg with the two rubber straps that are included.

The sheath and handle of the knife are bright green for easy identification if you drop the knife.


● Lightweight
● Brightly colored
● Sharp


● The locking mechanism can be difficult to use

Aqua Lung Argonaut Titanium Diving Knife

Aqua Lung Argonaut Titanium Diving Knife

$149.95 Amazon 

The Aqua Lung Argonaut titanium diving knife is one of the high-end dive knife options. At a higher price point, it has a 4mm thick titanium blade with EDP (electro-deposit primer) coating to prevent rust, corrosion, and ultimately preserve the blade of the knife.

The blade is 4 ⅞” long with a 5mm-thick handle that is wrapped in paracord. It comes with a 2mm-thick sheath that is made from thermoplastic. The sheath also has ⅛” grommets with 1” strap holes that are ¼” wide.

There are two rubber leg straps included with the knife and the sheath to keep in place when diving. The knife is durable and multifunctional with a pointed butt at the end of the handle that can be used for hammering and crushing.


● Durable
● Sharp
● Rust-resistant
● Multifunctional


● Pricey

XS Scuba FogCutter X Knife

XS Scuba FogCutter X Knife


Wouldn’t it be nice if your dive knife could also serve as a pair of shears?

Luckily, the XS Scuba FogCutter X Knife can do just that.

First, it acts as a dual-sided blade with a small serration on one side and a smooth edge on the other. This gives you the ability to cut different materials easily while underwater. The blade is 4 ⅜” long.

To turn the dive knife into shears, simply flip up the locking mechanism to release the two blades. The single handle will separate by the automatic spring. This will allow you to use the knife as a pair of shears to cut through net, wire, or other material.

The XS Scuba FogCutter knife comes with an easy release sheath that keeps the knife locked into place; however, many users suggest tethering the knife to a lanyard, as the knife can sometimes slip from the sheath. The sheath is then held into place by two rubber straps for you to safely and easily dive while wearing the knife.


● Multifunctional
● Durable
● Rust-resistant
● Easy to use


● Knife can sometimes slip out of the sheath

Spyderco Atlantic Salt Lightweight Folding Knife

This salt series knife by Spyderco makes it the most rust-resistant knife on the market. The 3.68” serrated blade is made from nitrogen-based steel. This type of steel is extremely resistant to rust and corrosion, which is ideal for saltwater use.

The serration pattern is Spyderco’s signature “SpyderEdge,” which makes it effective for any type of cut. It is a two-step serration pattern with two small serrations then one large serration. This pattern continues throughout the length of the blade. SpyderEdge pattern increases the cutting edge’s surface up to 24%.

The handle is 4.59” long and made of fiberglass-reinforced nylon, which makes it lightweight, durable, and comfortable. There is a metal pocket clip that keeps it fastened in place.


● Rust-resistant
● SpyderEdge serration pattern
● Lightweight handle


● No sheath, straps, or lanyard; will need to keep it in place by a pocket clip or another mechanism

U.S. Divers Titanium 5-Inch Diving Knife

U.S. Divers Titanium 5-Inch Diving Knife


The U.S. Divers Titanium 5-inch diving knife has a 5-inch titanium dual-edge blade with a serration edge on one side and a plain edge blade on the other. The blade is also equipped with a line cutter. The blade completely disassembles in the knife for thorough and easy cleaning.

The sheath has a one-handed quick-release button to easily remove the knife from the sheath. The butt of the knife is stainless steel with a hard rubber handle equipped with a lanyard hole. The hard rubber handle acts almost like plastic. It can deteriorate quickly if not well-maintained.

The knife and sheath also include two rubber leg straps for convenient and comfortable attachment to your body while diving. The entire knife is 9 ½ inches long and has a 2-year warranty.



● Titanium
● 5-inch blade
● Serrated and plain blade
● Stainless steel butt & rubber handle
● 2-year warranty


● Rubber handle deteriorates quickly

Why You Need a Dive Knife

As a diver, you know that what lies beneath the surface can be unpredictable. There can be fishing nets, lines, ropes, wires, or other entanglements that can trap you, your fellow diver, or other marine life. These entanglements can quickly become dangerous if you are unable to escape. Without a dive knife, you or the marine life may be unable to become disentangled from the net or ropes.

Marine life is unpredictable and can show up completely unannounced or uninvited. A dive knife can mean the difference in life and death if you are attacked by a marine predator. You may not have to kill the animal, but instead, injure it to scare it away, and the dive knife will allow you to do this.

In addition to becoming disentangled, you can also use a dive knife to anchor yourself during strong currents or undertow.

All of these scenarios make the dive knife a potentially life-saving tool that you should have while diving at all times.

How to Choose the Best Dive Knife

Dive knives can vary based on blade type, size, material, and attachment features. Let’s break each of these features down to get a better understanding of them. This will help you know which is the best dive knife for you.

Blade Edge & Tip

The blade edge can be serrated or plain, and the tip can be blunt or sharp. The combinations are endless.

  • Serrated edge – the edge of the blade with “teeth” or grooves. Serrated edges can easily cut through hard, tough surfaces.
  • Plain edge – the edge of the blade that is smooth and sharp with no teeth or grooves. Plain edge blades are recommended for clean cuts, like skinning an animal or peeling fruit.
  • Blunt tip – the tip of the knife is cut straight across and not sharp. This prevents the wetsuit from being cut by the sharp blade tip of the knife.
  • Sharp tip – the tip of the knife is sharp like a spear and can be used for stabbing.

Serrated edge knives are highly recommended for diving as they will be able to cut through tough surfaces, like ropes, nets, or other material; however, many dive knives have a serrated edge on one side and a plain edge on the other, which gives you the best of both worlds.

Dive knives with a serrated edge on one side and a plain edge on the other side with a blunt tip will be the safest and most effective dive knife.

Blade Size

As you will be using your dive knife underwater, it will need to be easily opened and wielded. A small blade will be easier to maneuver underwater than a large blade.

The ideal blade size for a dive knife should be between 3 to 5 inches. Blades that are bigger than 5 inches can be difficult and dangerous to operate underwater, and blades that are 3 inches or less are likely not large enough to be effective underwater.

For this reason, you will want a dive knife blade larger than 3 inches but less than 5 inches to be the most effective and easy to use.

Blade Material

Sand and saltwater will easily corrode and rust the knife blade. For this reason, the knife blade should be able to withstand frequent submersion in saltwater without rusting quickly. The best material to resist rust and corrosion will be stainless steel and titanium.

Stainless steel is less corrosion and rust-resistant than titanium. Stainless steel will require frequent cleaning after each dive as the saltwater and sand can quickly corrode and dull the blade.

Titanium is more resistant to rust, corrosion, and dulling. Titanium might cost more upfront, but the reward will be worth it.

Foldable or Fixed?

The dive knife can be foldable or fixed, and there are benefits to both.

Fixed knives are essentially quick and easy to use. Simply remove the fixed dive knife from the sheath, and it is ready to use. It’s a relatively quick and simple process.

Foldable knives will require time and effort to open the knife; however, they are typically smaller than fixed knives, which allows them to be more easily stored. Foldable knives are also considered the safer option of dive knives because they significantly reduce the chance of the knife inadvertently coming unsheathed and causing injury.

However, both foldable and fixed dive knives are sufficient and effective dive knives, and both have their own respective benefits.

Attachment Features

The dive knife will need to be attached to you in some way. This could be through straps, a tether, a lanyard, or a pocket clip.

The best method for attaching the dive knife to you is with straps. There will typically be two straps connected to the sheath of the knife, one located on the blade of the knife and one located at the handle. This will keep the sheath evenly strapped to your leg for quick and easy access.

The knife can also be attached to you via a lanyard or tether. This will keep the lanyard connected to you by a rope or string so that it doesn’t sink to the seabed without realizing it.

Another feature the knife may have is a locking mechanism that will keep the knife securely in the sheath. This is important as it will prevent the knife from inadvertently falling out of the sheath while diving.

Caring for and Maintaining Your Dive Knife

To get the most out of your dive knife, you will need to take care of it with routine and frequent maintenance, sharpening, and care.

Knives made of stainless steel will need frequent cleaning. To do this, you will need to remove the knife from the saltwater and immediately rinse it with clean, fresh water. Allow the knife blade to dry completely before storing it in its protective sheath.

Should your knife have any dirt or grime on the blade or handle, you can take some gentle soapy water to clean away the dirt and grime. Then you will rinse the soap completely and allow the knife to air dry completely before placing it into its protective sheath.

Mineral oil is recommended for dive knives that won’t be used for a lengthy amount of time. Mineral oil will help preserve the blade as well as protect it. Only apply a thin amount of oil to the blade before placing it into the sheath for storage.


When you are diving, you will need a quality dive knife. A dive knife can help you become disentangled from nets, rope, wires, or other underwater lines that can easily cause you to become entrapped. A dive knife that has a serrated blade edge can quickly and effectively cut through any of these rough materials so that you can free yourself, a fellow diver, or other marine animals.

You should try to find a dive knife that has a serrated edge on one side of the blade. This will help you be able to cut through different types of materials underwater. The other edge of the blade can be plain or have a line cutter; however, the greatest benefit of a dive knife will come from the serrated edge.

No matter what type of dive knife you choose, it is essential that you keep the knife well-maintained. Maintaining your dive knife regularly will ensure the dive knife lasts as long as possible without prematurely deteriorating. Simply rinse the dive knife off with fresh water and soap, if necessary, to remove salt, sand, and buildups of dirt.