What is the best diving knife

The best diving knives 2021 in comparison - "Under the Sea"


After the fishing knives, we would now like to introduce you to the best diving knives on the market and consider what features and properties a good diving knife should have.

But as always in advance for those in a hurry, my test winners:


Diving knife test winner

My top diving knife is the Eickhorn S.E.K. (Marine),
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My price-performance favorite is the Cressi Giant,
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Don't worry, I won't become a diver now, even if the lake almost in front of my door might be inviting, my new fishing hobby is currently enough for me.

I also think you don't have to be a diver to be interested in the special features or properties of a diving knife if you are interested in knives anyway.

And the die-hard knife collector, I would like to claim, is not necessarily interested in using the knife for its actual purpose. After all, it seldom happens that I walk around with my karambits and get involved in kung fu slaughter (or harvest rice while we're at it).

But speaking of it: what is the purpose of a diving knife?

Why a knife for diving?

To be honest, I had a rather divided relationship with diving, especially in view of the (shallow) depths and the necessary equipment (knife, diving watch, computer, ABC equipment). Even with video games, I feel very different when the character has to dive underwater for a long time.

For example, I remember an entire level in a Tomb Raider game that took place in an old shipwreck (am I that old?).

And that brings us to the topic, because Lara Croft not only had to defend herself against the sharks, but also pry open hatches, cut ropes or crack treasure chests, a matter of honor. And the whole thing, if you please, is quite jagged, because even a superhero can only hold her breath to a limited extent.

Admittedly, most recreational divers have less to do with treasure chests or sharks, but this example gives us a first clue. A diving knife is a tool that is used underwater to

  • digging or prying or cracking things and objects,
  • To cut lines or fishing lines,
  • to get rid of anything that could hinder you (fishing nets, algae or seaweed, depending on where you are diving),
  • to signal to the companions or to draw attention to oneself.

But diving knives are also used on land, for example for killing

  • To open mussels or oysters,
  • quickly tightening a screw or hammering something
  • or gutting the fresh catch on the boat.

Two priorities result from these application examples. Firstly, the diving knife should have a super sharp blade, which at the same time, secondly, is very robust. Robust enough to be able to pry something open, treasure chests or not.

The blade is of course not everything to look for when buying a diving knife.

Features of a good diving knife

Whether for leisure or professional use, a diver needs a high quality knife. But what does it exactly mean?

The following criteria are crucial and can help you find the right knife. We start with an overview and then go into more detail below on the individual points.

When buying a diving knife, you should look for these features:

  • Blade properties,
  • Cut,
  • Knife type (one-hand folding knife or fixed),
  • Handles,
  • Scabbard and attachment options,
  • Colour.

Diving knife in the test

You read that right, the color can also be relevant. But before I explain the individual positions to you further, I would like to present our diving knives in comparison, because the individual aspects can be better illustrated using specific examples.

1st overall winner - Eickhorn S.E.K. (Marine)

We already have the Eickhorn S.E.K. Police discussed in detail, therefore only the most important details of this top knife for professional emergency services in brief.

Because with a view to the police variant, the Eickhorn S.E.K. Navy "The same in navy blue" (not really, but because of the saying). It is a fixed knife with a total length of 21.5 cm, with a 10 cm long and robust 5 mm thick dagger combination blade. The total weight is only 140 grams.

The rust-free, robust N695 Böhler steel with a hardness of 58 HRC also ensures relatively easy-care handling. The handle shells are made of G10, which have an extra non-slip structure.

The difference between the police and the navy is the additional coating and fastening. This diving version is equipped with a DLC (which stands for "Diamond Like Carbon") coated blade, which also ensures corrosion resistance. And it has Velcro fasteners on the Cordura sheath for variable wear.

Unfortunately, the price is a disadvantage for many, because the Eickhorn S.E.K. Marine costs around 250 euros (when writing the article). So the question arises as to whether the knife is worthwhile for your own needs.

Conclusion: A top knife, both in terms of quality and functionality, for top demands.

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2. Aqualung Squeeze Lock - diving knife made of titanium

In my opinion, this knife impresses with its clear size. There can be advantages in opting for a shorter blade length. More on this below in the discussion of the details.

The Aqualung is "only" 17.5 cm long with a blade length of 7.5 cm. The combi blade itself - this is the highlight of the knife - is made of stainless steel, more precisely 304, with a titanium coating. More on that below.

The attachment of the scabbard is also well thought out. This is because it has a safety device that can be easily released using the "Squeeze Lock". Furthermore, it is a so-called jacket knife that can easily be attached to the Aqualung jackets in a variety of ways.

A disadvantage could be the handles, which at 8.7 cm could be a bit short for some divers, especially with gloves.

Conclusion: This jacket knife for divers costs 40 euros (when writing the article), and for that it is functional and convincingly good.

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3. Cressi Scorpio

The Scorpion is a very nice diving knife from the Italian company Cressi. The fixed blade is made of very robust and corrosion-resistant 420 steel.

It is not too big with its 10 cm. The total length, however, is already 23 cm. However, this has the advantage that the handles should be big enough for most divers.

As you can see in the picture, the Cressi knife is also a very versatile combination blade with a simple cut, a serrated edge on the back and a linen knife or hook.

The sharpness and edge retention of this knife are impressive - no matter how thick the rope may be, the scorpion cuts it cleanly, on dry land as well as in water. Nevertheless, the small line hook is very useful for cutting nets at lightning speed.

The knife sheath can be attached to the leg and has a locking mechanism that is bombproof and yet can be easily opened with one hand.

Conclusion: A solid diving knife at an absolutely fair price, which is around 30 euros (when writing the article).

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4. Mil-Tec Frogman

The Frogman from Mil-Tec is a cheap diving knife variant. The knife is priced under 20 euros (when writing the article) and thus clearly in the lower price segment.

Is that why it's cheap? No. For the occasional snorkeler or novice, the knife is simple, but rock solid. And for someone who is looking for a good all-round knife for water sports, the knife is definitely recommended.

The knife is not necessarily small. With a total length of 23 cm, it is even relatively long.

The fixed combi-blade including the line hook made of stainless steel is 12 cm. The rubber handle is just that - very handy - and absolutely non-slip.

I particularly like the variant with the salamander-like Lurchi color, which is well suited for signaling, but also for finding knives again should it ever fall into the water.

Conclusion: ideal for getting started. With cheap knives I always fall into the same trap that I neglect maintenance compared to high-quality knives. This then leads to the knife becoming unsightly faster than it should. But then it had been cheap and had done its job well.

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5th price-performance winner - Cressi Giant

Finally, my price-performance winner. With a total length of 30 cm and a blade length of 17.8, it is truly a giant, a "Giant".

What impresses with this impeccable quality knife is, in the truest sense, the clip point tip of the blade, which is made of 304 steel with an extremely corrosion-resistant black powder coating.

As with all knives, this is also a combination blade with a serrated edge that is really very well executed.

In addition, we were also impressed by the rubberized handles and the locking mechanism of the knife in the plastic sheath, which in turn can be released via a simple pressure point.

The knife can be attached to the belt or to the leg with two loops. I also noticed the hammer at the end of the pommel.

As with the Eickhorn, one can criticize the "tactical color" of the knife, because if you only do recreational sports and do not want to hire the Navy Seals, a knife with a clearly visible luminous color under water would be an advantage (see below).

The point in particular is not suitable for everyone, as I will also explain below.

Conclusion: You can hardly ask for anything better - for the price of around 65 euros (when writing the article), that means.

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Diving knife in detail

Away from the specific and towards the general. I will discuss the properties of a good diving knife in detail below.

Now that we've looked at some diving knives - all of which can be recommended individually - we've already learned a lot about them, and we'll start with the most important one, the blade.

Blade and bevel - 6 basic properties

You should always pay attention to the following properties of the blade:

  1. stainless blade material,
  2. the blade sharpness and sharpness properties,
  3. the blade thickness,
  4. the cut,
  5. the shape of the blade,
  6. Corrosion resistance.

Stainless steel…

The blade material of a good diving knife is usually made of stainless steel, logically, or titanium or a corresponding alloy.

This material offers stability and toughness, is relatively corrosion-resistant and has good edge retention. Nevertheless, it should be emphasized that these blades must also be treated with care.

This also applies to stainless steel, especially when diving in salt water. Note that stainless steel also rusts, so the popular term “rustproof” is misleading, such steels are indeed rust-resistant.

... also needs care!

The knives should be cleaned with fresh water after the dive and dried thoroughly. This means that it is best to let the knife dry out completely outside of the sheath or in the unfolded state.

The blade can also be oiled. Especially when the steel is in the 400 range.

A rough donkey bridge: the higher the number of the steel designation - 440, for example - the more sharp, the lower, the more corrosion-resistant. And vice versa.

So everything has advantages and disadvantages: either you have to sharpen it more often or you have a higher need for care.

Diving knife made of titanium

Titanium knives or blades with a titanium coating such as the Aqualung Squeeze Lock, number 2 on our list of the best diving knives, naturally offer very special advantages.

They are even more stable and resistant to corrosion and wear. All of this in a stainless steel blade, and the knife will serve you very well for a very long time.

Of course, this is all the more true when the entire blade is made of titanium. These blades are also more flexible than steel blades and therefore do not “break easily”.

In addition, titanium blades are extremely easy to care for and have a good edge retention, and of course lighter than other steel blades.

But titanium blades are much more expensive and still need to be properly cared for to keep their quality for a long time.

Blade size

If you know the pop culture of the eighties, you know that for real guys, especially in the outdoor area, size is everything. Crocodile Dundee would certainly not agree with me, but a small or medium-sized blade is perfectly adequate for a diving knife.

That means 5 cm to 12 cm. Anything beyond that can easily become unwieldy.

Especially when you opt for a fixed knife, there is also the length of the handle. And using a knife underwater is not the same as on land.

But a really large diving knife is not necessary for the corresponding work, and could even be a bit dangerous to use.

For recreational divers, 8 to 10 cm are completely sufficient, also to be able to free themselves from a net if necessary.

Tip Blade length equals handle length

Smaller knives, straight pocket knives, may be even more practical, but please make sure that the handles are long and large enough, even when wearing gloves, that you can grab them safely.

As a rule of thumb: ideally, the size of the blade, 10-12 cm, should roughly correspond to this handle length.

Sharpening and knife point

First of all, a distinction should be made between a simple smooth cut and a serrated cut. That both types can be relevant for divers is shown by the large number of diving knives with combination blades.

The other aspect that I want to go into further is the tip of the knife. Pointed and blunt variants can be found here. But first the cut.

Smooth or serrated edge

The smooth edge is suitable for cutting plastic, linen and nylon. Most diving knives also have a line knife or hook.

This is particularly suitable for thin fishing tendons or lines that you could get caught in.

The serrated edge is better suited for tearing cutting of fibrous material - in plain language: ropes, for example. Or also for sawing, for example from thick bones. The serrated edge stays sharp longer, but is also more difficult to sharpen compared to the smooth edge.

The tip of the knife - pointed vs. blunt

A blunt point is perfect for prying something open, digging, chopping, or using the knife as a chisel.

You don't have to worry about security either. Because with a blunt knife tip you are guaranteed not to puncture a hole - accidentally - in the air hose, the neoprene suit or even in other divers.

But if you want to do exactly that - no, not injure the other divers, but perform precise stitches for other reasons, then of course you choose a pointed blade.

For example, if I want to gut my fresh catch right away. And if you briefly think about what that means, then it immediately becomes clear why diving knives do not necessarily need a blade thickness of 5 mm or a blade length of 15 cm. More on this in my overview article on the fishing knife.

Tanto tip for diving knives

But back to the topic. As a rule of thumb, very sharp knives are less recommended for divers. The Tanto knife is a hybrid variant, a good compromise for divers.

Because the Tanto blade combines the stability and strength of a blunt blade with the cutting edge and the piercing quality of a sharp one.

Folding knife or fixed blade?

Of course, fixed full-tang blades are always more stable and robust than folding knives. But in the meantime there are already such good folders on the market, with extremely strong locks, that folding knives should not necessarily be excluded as diving knives.

They are of course smaller, lighter and therefore perhaps more convenient to carry with you. They are definitely safer than fixed blades.

However, the question then arises as to how easily the knife can be opened, especially in an emergency. Is it a one-hand knife or do you need both hands? Then things could get tricky if things have to be done quickly.

As always, the general question arises as to what you want to use the diving knife for. But the tendency, as my selection above also shows, is still in the direction of fixed blades, especially for professional use, which can be a matter of seconds.


How often have we tested knives and rated their slip resistance and grip, and how often have we pointed out moisture and other influences? Right, very often, actually every time.

But with a diving knife - quite clearly - this becomes the top priority. Here an almost aggressive rubber coating is desirable, you can imagine that.

But in contrast to the other knives - outdoor, bushcraft or survival - it is less important that the knife is particularly ergonomic or has no hot spots, i.e. does not cause any sores. You can safely neglect these aspects.

Mainly because you handle it in the water, often wear gloves, but also don't work with it for a long period of time. Diving knives are used for selective use.

There is often a hammer at the end of the handle, the pommel. Of course, this can never hurt as a tool for hammering or hitting. But when diving, these metal knobs also serve to draw the attendant's attention to us in front of us, for example by knocking them on the tank from behind.

The knife sheath

The sheath of a diving knife is very important and should have at least two characteristics. And, ideally, best to be tested underwater.

On the one hand, the knife should be secured when you don't need it and sit firmly in the sheath. After all, the knife shouldn't just be able to say goodbye on the go. On the other hand, it is very important that you can easily pull the knife out of the sheath with one hand.

If this is not the case, it can lead to panic, especially with beginners - I can understand that personally - and that must be avoided in any case.

If you opt for a folding knife, then the diving knife should have a strong belt clip or something similar.

Attachment options for a diving knife

Essential for a diving knife is not only a robust, safe and at the same time smooth-running knife sheath, it is also important how it can be attached.

Depending on your requirements, you can choose between different variants. Most knife sheaths can be attached to the arm or leg. Some attachments are also designed to be attached to the equipment itself - such as the BC knives.

Basically, the taste decides here. However, this device, no matter which device, should also sit securely and firmly and, if the diver is tangled in a net, be quickly to hand without any major detours.

In addition, eyelets are desirable so that you can secure the grip - for example when working in strong currents. If the knife slips out of your hand, it cannot drive away.

Color and visibility

Some diving knives have glowing neon handles. This is not a fashion trend, it is pure function.

These colors increase visibility. This can help to locate the knife under water more easily if it slips out of your hand.

The visibility can also help to signal something to the diving colleagues or to increase your own visibility.

I wonder whether the "Lurchi" color of the Mil-Tec Frogman could not also have the same function as the color of the fire salamander, i.e. also act as a warning signal.

In any case, however, it is precisely this increased visibility that is the reason why professional, tactical knives like the Eickhorn S.E.K. Marine do without it.

As a diving knife as a lifesaver

A diving knife can save lives. The knife must be ready for use in a flash, especially under water. Here is an overview of the most important criteria.

A good diving knife

  • has a blade made of rust-resistant steel, also with a titanium coating,
  • is very sharp and sharp,
  • is corrosion resistant,
  • has a strong blade,
  • is relatively easy,
  • has a metal knob or hammer,
  • has signal colors on the handle,
  • has a secure attachment.

Off to the diving vacation

Please note when you take the plane on your next diving vacation: The diving knife does not belong in your hand luggage! Although the blade should not be excessively large, the knives will most likely be confiscated during the inspection.


I already mentioned my split relationship. I am fascinated - why else would I have wanted to see the long film “Abyss - Abyss of Death” five times in a row in the cinema (!) And then buy the best diving goggles straight away?

But the grandeur of the sea troubles me. Or maybe that's the whole point and my subconscious just needs a good diving knife?

Let's leave the nonsense. The diving knives presented above and my catalog of criteria may help you to find the best diving knife for your needs.

As always, it depends on what exactly you want to do with the knife, how often you want to use it, where you dive, and so on.

Either way, you should take the time to think twice about your purchase - a good diving knife can save lives.

All of the diving knives that we have discussed are all recommended, but the highly professional Eickhorn S.E.K. may not be worthwhile for all of them. Marine or others are not sharp enough or corrosion-resistant enough for you.

As always, the decision is yours.

What do you think are the most important criteria for a good diving knife? Which diving knife is your favorite?