Do I Really Need a Dive Knife? Is it safe? Scuba Knives Explained


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The standard diving equipment, which consists of diving fins, diving masks, neoprene suits, BCD, and diving computers, can be expanded with various accessories. This also includes a dive knife. A dive knife is often used by divers as a tool: The blade is suitable as a pry tool, as a cutting tool, hammer, and digging tool.

While diving is taken as a hobby for most people, some take it further as a sporting activity. A few people, like those in the military – navy divers or combat divers, engage in diving as a part of their profession.

Therefore, some (particularly those who take diving as a hobby or sporting activity) may find having a dive knife as a part of scuba diving accessory as being extreme or unnecessary. Hence, the consideration is; “Do I Really Need a Dive knife?” and “Is it safe?”.

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Do I Really Need a Dive knife?

To answer this, it’s important to know why you need a knife when diving.

Why do you need a knife when diving?

For freeing from Ghost nets and lines, ropes, and fishing lines:

Dive knives can be a real lifesaver in some cases. If the diver gets tangled in a line, a sharp and sturdy stainless blade becomes essential under the water.

A good diving knife easily cuts through ropes, lines, fishing lines, and fishing nets (so-called ghost nets) that you get caught in while diving.

It doesn’t even have to be the tropical ocean – the local bathing pond harbors no less problematic dangers because orphaned nylon fishing lines are often left underwater, which can wrap around a foot or protruding equipment.

When you have a dive knife with you, in a case where your dive partner gets caught, you can be of help.

Read about the differences between dive fins and snorkel fins here.

For Nature Conservation:

It is becoming more and more common to observe animals underwater that are caught in all kinds of human rubbish. The problematic culprits include the same lines, nets, and cords as mentioned. Every year, thousands of fish, sea turtles, marine mammals such as seals, dolphins, and whales perish in agony in fishing accessories that are mostly lost from fishing boats. Thus, the dive knife has indirectly benefited nature conservation.

Sending acoustic warning signals:

Many diving knives have a metal knob. If you hit it against the compressed air cylinder, you can send out an acoustic signal used to attract attention, such as hitting the scuba tank and generating signal noises in this way.

Defense against dangers:

Even if this only happens extremely rarely, dive knives can be used in an emergency to ward off dangerous underwater inhabitants. Without dive knives, divers face an insolvable problem, as the lines, ropes, and nets made of tear-resistant synthetic yarn cannot be cut without the use of a knife. You therefore need a dive knife, they are indispensable at certain times in the water and should be carried with you on every dive.

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Is it Safe?

Dive knives, which can be particularly practical under the water, provide additional safety for you. They are real lifesavers, especially in emergencies. Generally, if a Scuba knife is used for its primary purpose, its safe to be used in diving.

For safety, the shape of the knife needs to be put into consideration.

Diving knives are available in different shapes. For instance, differences between dagger knives with a sharp blade on both sides and the versions with a sharp blade only on one side. You also have the choice between fixed knives and folding knives. Furthermore, the blades can be rounded to a point or blunt. However, with pointed, rounded blades, it should be noted that there is a greater risk of accidental injury.

Furthermore, a dive knife is not to be treated as a weapon but as a safety tool. Dive knives should not be misused to remove annoying diving buddies under the water. They are not also intended for underwater hunting. Instead, dive knives are used as tools or as life-saving appliances. Before daring to rescue a potentially dangerous animal, ensure you have enough experience on how to use a diving knife.

Under no circumstances should a diving knife be used to damage, cut off, or even kill corals or other underwater creatures!

Read about the different fishing rod types and uses here.

A knife offers a significant safety advantage, especially in diving areas that you have not been to before. Therefore, we can say it’s safe always to have a dive knife for every dive.

It’s also important to know how a dive knife should be carried, for the reason of safety and proper use:

How should a Dive knife be carried?

Several models come with the actual knife as well as a knife sheath and various attachment options. For medium-sized to large knife models, attachment to the leg or arm with knife bands is common. These knife tapes are usually made of flexible plastic. With them, the diving knife is fixed to the calf, for example, using a buckle or another quick release.

Smaller diving knives are called “jacket knives” from time to time. This name comes from the way the knives are attached. These are attached to the pockets of the jacket, on the corrugated tube, or newer jackets to the extra fixing points. Two suitable screws or simply one or two cable ties are used for this purpose.

Another fastening option can be found on the inflator hose and the hose of your dive computer or instrument console. The fastening clips provided for this purpose are included with the appropriate knife models.

Which of the mentioned carrying methods you prefer is fine.

Furthermore, the possibility of having a dive knife attached, depends on your diving equipment. For children, smaller knives ought to be used more often.


A Scuba Dive knife is a must if the worst comes to the worst while in the water. It is a necessity for your safety. When you may need to free yourself from threatening situations, they will be really helpful. Therefore, for safety in the water, you do really need a dive knife, and it’s safe to use.