A lot of beginner divers wonder whether they really need the best dive knife. Is it a mandatory diving gear? Can’t you just dive without it?
Sure you can. There’s one problem though. Fishing line. Believe it or not, our ocean floors are clogged with fishing lines. What’s worse is that they are near impossible to see and definitely impossible to break out of.
That’s where dive knives come into the picture. It can be lifesaving. Not just for you either. Time and again, you may come across marine life entangled in fishing lines. A dive knife can help you save these gentle animals.
If you pictured yourself cutting open a Great White Shark underwater with a dive knife, sorry to disappoint you.
Coming back to the best dive knife, there are hundreds of them on the marketplace. Not all of them are cut from the same cloth though.
How do you buy one that lasts a long time and doesn’t cost an arm and a leg? That’s where I step in with this guide.
I dove deep into the murky depths of the dive knives marketplace and cherry picked the best of the lot for you. So strap in and enjoy the dive.
Best Underwater Diving Knives – Top 10 Review
#1. Atomic Aquatics Ti6 – Best Titanium Dive Knife
Atomic Aquatics Titanium Ti6 is a compact, lightweight titanium knife with a full tang blade. It features a curved cutting edge on one side, a serrated edge on the other and a dedicated line-cutting notch in case you get entangled and don’t want to fiddle around too much.
Just use it and viola. You are free to explore the blues again.
The Ti6 is sharp, multipurpose and corrosion resistant, which translates into years of unhindered usage underwater.
Blade – 4” full tang blade
Handle – 3.5” sturdy plastic handle with finger grooves for a slip-proof grip
What I like about it
There are quite a few things that I like about this knife. At the forefront is the blade quality.
- It’s as tough as they come. Can definitely double up as an EDC for more uninteresting tasks around home, such as cutting zip ties for instance.
- Secondly, the sheath is a brute. It retains the knife like a charm, which can be a little tricky for new divers.
- More importantly, the quick release catch ensures that you are able to grab the knife with one hand in emergency situations.
The straps are 17” long, which may not be enough for some people trying to mount this on the thigh. There’s an easy workaround for this. So it’s definitely not a deal breaker. Also, it might be a little big to fit into a BCD pocket.
This is a great choice for both, beginner and seasoned divers. It’s compact, practical and will get you out of an entanglement in no time.
The Promate Titanium Knife is a lightweight and reasonably priced option for divers who want to test their gear without breaking the bank. But don’t let the affordable price tag fool you. This is a powerful titanium dive knife with a strong blade that sports a razor sharp edge, right out of the box.
Like most dive knives, it is available in both pointed and blunt edge configurations. Regardless of whether you aim to gut Godzilla, or use it for more regular activities like cutting fishing lines, this will get the job done.
Blade – 4.5” Titanium with curved and serrated edges on each side
Handle – 5” rubber molded handle for an easy grip
What I like about it
It’s lightweight at 4.5 oz, but has great heft and balance. When you take it out of the sheath, which is very easy thanks to the push button release, you will feel the knife in your hands. This makes you less likely to drop it. Bonus points for the rubber molded handle and the firm grip you get every time.
The full tang blade can cut through anything that you throw at it. There are people who have cut through cordage with it with no problems at all. By the way, this knife also features a dedicated line cutting notch like the Ti6.
The ABS plastic sheath is not the most pliable one. That does not affect the functionality or access of the knife in anyway. But a lot of divers prefer pliable sheaths and this isn’t one. Also, the blunt edge hammer at the edge of the handle is a little flimsy for the advertised use (tank banger).
Despite a few minor quibbles, this could well be the best underwater knife for the money.
The Aqua Lung Argonaut is a fixed-blade brute of a knife that’s crafted from a single piece of 4mm Titanium. It features a tactical design with a black EDP coating and paracord wrapped handle. A neat addition is the 5” leash that can serve multiple purposes.
The knife comes with a 2mm thick Kydex plastic sheath that offers ample protection for the blade. Underwater, the knife is easy to retrieve and place back into the sheath without fumbling around too much. It’s a snug fit, so you won’t find the knife missing when you make your way back to the surface.
Blade – 4 7/8” Titanium with black EDP coating
Handle – 4 7/8” wrapped with paracord
What I like about it
The Aqua Lung Argonaut is a no-frills attached military dive knife. It does not boast of fancy features. Yet, it will tackle most things that you throw at it, including thick three-strand lines and the occasional curious shark.
You have two edge choices, a blunt tip one for prying and a spear head point for piercing. Both options come with a sharp factory finish and will be ready for use out of the box. The paracord wrapping is ½” under the hilt which gives you enough room to place your forefinger for extra grip during cutting tasks.
Nada! This is perfection at its best.
The Aqualung Argonaut can also double up as a great fixed-blade EDC for general camping use.
The Barracuda is one of Promate’s bestselling dive knives that ticks all the right boxes. It is available in both stainless steel and titanium blade configurations. I prefer this Titanium one because it is about 50% lighter and hence, easier to carry as well as handle.
You can choose from a drop-point edge or a blunt tip for prying, which can also double up as a screwdriver in emergency situations. The Barracuda features a plain edge with a double bevel on one side and a slightly smaller plain edge with large serrations on the other side. At the bottom of the plain edge side, you have the mandatory cutting hook.
Blade – 5” Titanium with curved and serrated edges on each side
Handle – 4.5” heavily contoured handle for a secure grip every time
What I like about it
The Barracuda ships factory-sharpened and a little bit of work with a fine-grit sand paper is all that it takes to hone that edge to cut smooth filets from the catch of the day. While it does feature a fine line cutting hook, you are not going to need it because that edge will make short work of monofilament line anyway.
On the other side, the serrations are bigger in size than what you see in comparative models. The pattern is wavier which makes it quite a formidable force against heavy three-strand line. Finer serrations tend to get stuck in these.
The Barracuda is easy to disassemble, which is more important than it seems to be. If you dive in sandy areas, you’d want to take the knife apart before rinsing it clean.
The retention clip on the Barracuda’s sheath is a spring plate with a catch. This design, while very effective for retaining the knife and easy access, is prone to accumulate tiny grains of sand, which can then interfere with the mechanism.
The Barracuda is a terrific sharp tip dive knife. It has one of the best serrated edges I’ve seen. Moreover, Promate is one of the most reputed brands in the business. Hard to go wrong with it.
The Underwater Kinetics Blue Tang is a sleek, titanium dive knife that features a two-tone handle. It’s black with yellow accents, which can be a welcome change from the tactical designs that are commonplace now.
For one, the knives should be easier to locate in case they get misplaced.
Coming back to the knife, it is 100% corrosion resistant and non-magnetic. Features a hollow ground straight edge on one side and a serrated edge on the other. The butt of the handle features a titanium hammer for tank banging in an SOS situation.
Blade – 5” Titanium full tang
Handle – 5” curved with minimal contouring
What I like about it
The UWK knives feature a full-sized blade which makes them more durable than run-of-the-mill options. Another great feature is that the design avoids metal to metal contact because it prevents corrosion.
When you disassemble the knife, you will notice a plastic connector in between the edge of the blade and the titanium pommel/hammer.
The curved edge with minimal contouring may or may not work for you. Some people may find it too slippery for one hand operation. So do consider this before you shop.
If you have handled knives with minimally contoured handles, you are going to love the Blue Tang Titanium. By the way, Underwater Kinetics knives are proudly made in the USA and not imported from Taiwan.
The TUSA FK-940 X-Ppert II is a versatile diving knife with a very practical design. The versatility comes from the dual edges and the cutting notch at the base, which expand its capabilities, both under water and outside of it.
Be it slice cuts or saw-type cuts, the strong blade makes it effortless. The non-magnetic titanium design is perfect for scuba use. Add to that a high-visibility red casing and accents and you have a knife that you can spot with ease amongst a hundred others that look identical.
Blade – 4 ½” Titanium full tang
Handle – 5 ½” with an ergonomic design and a counterweight for balance
What I like about it
The TUSA screams quality. Be it the sturdy blade or the durable sheath, this is a quality piece of diving equipment that should last long with minimal maintenance. The counter balance in the handle seems gimmicky when you read about it. But it really makes a huge difference in the balance of the blade when you are working under water.
I also like that the case has a single-button (ambidextrous) sheath lock release that makes it effortless to grab the knife with one hand.
The seller often ships the wrong color. So if the shiny red case is a motivator for selecting this one, then I suggest you reach out to them to avoid a faux pas.
The Tusa FK-940 X-Pert II matches much higher priced stainless steel dive knives in performance. But it costs much less and does not weigh down your wet suit.
#7. Spyderco Atlantic – Best Stainless Steel Dive Knife
It’s not every day that one comes across a folding knife that performs as well as a fixed-blade, full-tang option. That too underwater. Enter the Spyderco Atlantic.
It’s everything that the rest of the best dive knives aren’t. It just has a serrated edge. No straight edge with the line-cutting notch. It’s H1-Steel, not titanium.
Yet, this Japanese-made folding knife is one of the top rated dive knives in this list.
Blade – 3.6″ H1-Steel
Handle – 4.3” fiberglass reinforced nylon (FRN) with a volcano grip
What I like about it
The Spyderco Atlantic with its hollow-ground H1-steel blade offers remarkable performance that is on par with the best full tang titanium knife you can find. It does not rust, ever. It does not yellow when exposed to salt water either.
While the lone serrated edge might make it seem limiting, this can cut through practically anything under water. If the edge ever gets dull, you just need to send it back to Sypderco (you pay the shipping) and you get it sharpened for free.
Mounting this will require some elbow grease because it does not come with the conventional sheath and strap set up. It’s nothing that a paracord and a D-ring cannot solve though.
The Spyderco Atlantic is a terrific dive knife. It has great reviews from professional divers too. The added advantage is that it doubles up as an EDC when you are not busy exploring the ocean floor.
#8. Cressi Skorpion
The Cressi Skorpion is a medium-sized fixed blade knife made by the Italian brand that’s considered a pioneer in spear fishing and diving equipment. There are quite a few things that separate this from the rest of the knives in this list.
For starters, it is a stainless steel knife. Before you raise eyebrows, it is 100% corrosion and rust-free steel alloy. It is a tad heavier than the titanium ones, but that’s expected with the steel construction, isn’t it?
Blade – 4 3/8” tempered AISI 304 steel
Handle – 5” Soft grip plastic
What I like about it
This is a perfect diving knife with dual edges and a hook for line cutting. The ergonomic handle provides you with a firm grip every time, and the quick-button release allows for easy, one-handed operation underwater.
For a change, the straps are long enough for mounting high on the thighs even for tall divers.
There have been a few complaints about the knife hilt rusting after a few dives. However, these complaints are sporadic and not frequent enough to consider it a design flaw.
This is a terrific stainless steel knife from one of the most reputed brands in the industry. It’s compact and fits like a charm in the sheath.
The FogCutter X is a sturdy diving knife with a tough stainless steel blade that features Patented ‘Shears’. Oh yes, a quick release mechanism turns your knife into a fully functional shear that can cut through the toughest fishing line or kelp.
While such a design could be riddled with flaws, XS Scuba has perfected it. There’s absolutely no problems whatsoever unlocking the knife, locking it again or using it, all with one hand.
Blade – 4 3/8” Stainless steel with an integrated shear
Handle – 7” molded plastic for a firm grip
What I like about it
The FogCutter is a beast of a dive knife that can cut through anything. It features dual edges, one straight and one serrated. In the rare event that neither can tackle the material you are trying to cut, the knife transforms into shears.
It fits snugly into the sheath and the locking mechanism has an audible click that’s impossible to miss. Comes with two straps that let you mount it on your thighs with ease.
As much as they advertise that 420 stainless steel is 100% rust free, it depends on the quality. So always clean and dry the blade before you tuck it away after use.
Excellent stainless steel dive knife for both lake diving and deep sea use. Versatile design that greatly expands the possible applications of the tool.
The Aqualung Squeeze Lock features a patented design that allows divers to release the knife from the sheath with a gentle squeeze on the handle. If you hate release mechanisms, or tend to fumble while trying to release a knife under water, this is just what you need.
Also, this is the smallest best dive knife in this list. It’s just 6” overall, which means that it can easily fit the BCD. Despite the pocket-sized form factor, the knife is tough as nails. It’s a double edged one with a cutting hook. While I have listed the titanium one, it is also available in stainless steel.
Blade – 3” Beta Titanium alloy
Handle – 3” molded plastic with quick-release squeeze design
What I like about it
The Aqualung Squeeze Lock Dive knife is so compact that it can be mounted anywhere. The options are the BCD, a hose, a belt or your thigh. It’s so light that you won’t even notice it. But come an emergency, you can release it in the blink of an eye. The handle also features a lanyard hole to keep it secured during dives.
It is also one of the only knives that is available in three tip options that are Blunt, Stiletto, or Tanto tip.
The serrated edge tends to come with burrs at times. So you might want to check the knife when it arrives to ensure that its burr-free.
The Aqualung Squeeze is truly pocket-sized. But it can cut through the toughest of materials. The tactical design and the practical features are on par with a navy seal dive knife.
How to Select the Best Scuba Knife
A great dive knife is probably the only diving equipment that rarely gets its fair due.
But come dive time, it dons many capes and effectively too. It’s rugged enough to be used for prying without snapping. It is sharp enough to cut through line and cords. When the situation demands, it can double up as a screwdriver and a hammer.
It can slice, dice and saw with equal élan. It’s no wonder then that you have to be selective about your choice.
Here’s a brief checklist to evaluate the best dive knife before you shop.
The Cutting Edge
Dive knives generally feature dual edges. One side with a straight edge and a curved belly for more effective slices, while the other side features a serrated edge for sawing. While picking the serrated edge, rounded waves or serrations might be a better pick over pointy ones. The latter are prone to snags. A line cutting notch is a good addition, but not necessary. I have rarely seen divers trying to cut monofilament with the notch. They will go at it with the sharpest knife edge and it works just fine.
The tip of the blade is an underrated aspect of selection. Dive knives feature three types of blades.
- The Blunt tip which can double up as a screwdriver, and be used for prying
- The pointed tip which can be a spear point or a drop point, which is very useful for piercing.
- The Tanto tip which is a hybrid of the two
Your choice should depend on how comfortable you are handling the knife underwater, and the intended applications.
For instance, if you are a little clumsy while sheathing the knife, the blunt tip might be a better choice. There’s always the risk that you might stab yourself or your BDC while sheathing with a pointed tip. On the flip side, if you want to cut into a thick knot of rope, a pointed tip knife might be a better bet.
Consumer grade dive knives are made of stainless steel or Titanium. Most divers these days prefer titanium because it doesn’t rust and offers much better corrosion resistance as compared to stainless steel. Also Titanium blades are lighter than steel. That said, some old school divers still trust their stainless steel knives and are quick to dismiss any concerns of rusting.
A knife under water will only be effective provided you can grip it firmly, without it slipping away. That’s why it’s important to pay equal attention to the handle. Is it contoured? Is the material soft?
Sheath and Release
The sheath holds the knife securely during the dive. But allows you to quickly release the knife with one hand. Pay attention to the release mechanism. A spring loaded quick-release is the most popular one these days. Sheaths will also determine how you can mount the knife. If you prefer mounting it on the legs, ensure that the sheath includes double straps.
Choosing the best dive knife just got easier, didn’t it? I hope that this list helps you find the ideal knife for your diving trips. Stay safe underwater and enjoy your dives with your trusty knife in tow.