This guide explains what a scuba diving knife is used for, and what makes a good knife for a beginner. We also list the top rated dive knives in 2023 with reviews from our team.
A dive knife is a general tool and a safety device for scuba divers and in spearfishing. You can use it to cut yourself free, such as if you get entangled underwater.
The material used by manufacturers to forge (cast) the metal part of a dive knife will be titanium or stainless steel. But, you should never use it:
So, you can attach it to your scuba equipment, or you can wear it on your lower body using a leg strap. The sheath needs to hold your knife securely, yet allow you to release and secure it with one hand.
Cheap dive knives are made from stainless steel. The titanium versions are more expensive, but they will last a lot longer - unless you lose it.
Beginners should consider it as being a tool for general use and for safety. Even so, the main purpose of carrying a knife with a serrated edge while diving underwater is to be able to cut fishing line (e.g. for preventing underwater entanglements).
Most large knives have a metal handle butt which can also be used as a hammer. This comes in handy for getting your buddy's attention by banging on the metal scuba tank. This isn't a common feature on small, compact knives because they tend to be too scaled-down for rapping on the cylinder.
In general, the best diving knives all have several functions and features that make them a useful underwater tool, including:
The "unsharpened" top section of a clip point knife looks like it has been trimmed (clipped off). This shape is good for piercing objects and the cutting edge tends to be long and curved.
The spine of the drop point blade is not (usually not sharpened). Most of them have a gentle convex arc that runs down to the pointed end. Despite not being the best diving knife for penetration, they have a strong tip and a long cutting edge.
The standout features of this strong, wide-bladed diving knife are the two convex edges. Though not symmetrical, the two curved edges tend to have a sharpened tip and a long cutting surface.
If you want to buy a dive knife for tight spots, such as when diving inside shipwrecks, the sheepsfoot diving knife could be the ideal tool for you.
This particular type features a straight cutting edge and a blunt, somewhat rounded tip. The manufacturers make them with serrated and smooth edges, which helps to reduce unintentional cuts and punctures.
An ideal device will have a scabbard and a retainer so you can mount it on your dive gear, most often the BCD, the back of the gauge console, or strapped to the inside of your calf or forearm.
There are many different styles and sizes of scuba diving knives to choose from. But, we recently reviewed the Promate dive knife model - and here are the results.
This diver's tool definitely has a sleek design. However, the most notable features are the robust finish and comfortable leg straps for knives.
The blade is made from lightweight titanium, so the edges should stay sharp for many dives. The handle has an easy grip and there are sharp or blunt tip designs available.
Note: Another section contains a comprehensive list of scuba dive equipment and accessories. It is a useful resource guide for anyone looking to buy cheap scuba gear.
The proven design of this essential scuba accessory device is what you might expect from the Dragonfly 2 platform based in Japan.
After reviewing the product, one notable feature has to be the robust corrosion-resistant quality of H-2® steel (an advanced nitrogen-based alloy).
The claw-like cutting power of the hawkbill blade and tapered tip pierces through objects (e.g. line, netting, and other fibrous materials), before collecting and drawing them into the concave edge.
Note: It's fair to assume that the distinctive design of this underwater diving tool resembles the hawk-like appearance of the hawksbill sea turtle (Eretmochelys imbricata).
The Mako diving knife is strong and lightweight, made from hardened titanium. The corrosion-free cutting performance is one reason why it's a popular choice for divers.
In other words, the titanium blade is incredibly robust, it resists rust, and it has the hardness to take and hold a sharp edge.
Despite being small and compact, you'll find plenty of gripping area in the handle. Plus, the thumb guards help to prevent it from slipping.
Note: Click through to our scuba diving accessory section for even more gadgets, gizmos, and scuba toys with reviews.
If there is a simple yet strong diving knife that suits almost all divers, it could be the Hog Pro scuba knife, distributed by EDGE GEAR.
Having a powder-coated four and a half-inch blade (less than 12 centimetres) means it's durable, it looks great, and it has two optional rubber leg straps.
The grooves on the molded handle make this Hog Pro scuba knife one of the best dive knives for comfort and for mounting on a B.C.D.
Note: The main section contains even more scuba diving gadgets that add extra fun and enjoyment for divers.
There are several contenders for being rated as the best titanium dive knife on the market. But, having a price tag around one hundred dollars, means this could be the one.
This black, lightweight, corrosion-resistant small scuba knife is a tough beast, measuring less than twenty one (21) centimetres in total length (8.26 inches).
The short, stumpy blade, made from rust-proof titanium, features the modern and trendy serrated sawing edge design.
Having a dual-edged cutting tip and line cutter means this compact tool fits nice and snug into the palm of your hand.
Note: Click through to our scuba accessories and gadgets section for even more cheap scuba gear and equipment reviews.
Some kind of lightweight tool with a sharp edge for cutting line is essential for all divers. Even the point, or blade, of an underwater dive knife will help you free yourself, your buddy, or rescue trapped or tangled up marine life.
Pro Tip: You might also use a good dive knife (e.g. one with a long blade) for extra stability on the floor of the ocean. This could be useful to know when Drift Diving in fast-moving currents, for example.
Most general use tools for divers are made of stainless steel or hardened titanium. Being lightweight is the main advantage of using a silvery grey corrosion-resistant metal.
Nonetheless, a diver's knife made with stainless steel will stay sharp longer and they will generally be less expensive to buy than many of the titanium brands.
The list of equipment needed for spearfishing is quite short, but it should include a sharp-edged tool. Plus, choosing one with a serrated edge will be handy for cutting sea kelp, large plants, and rope.
But, the best spearfishing knife will have a line-cutter for slicing through old monofilament fishing line and a sharp point for 'dispatching' the catch.
The WASP Injector Knife is a multi-shot gas injection device designed to be effective for defence against predatory animals in the sea (e.g. such as when freediving with sharks in the water).
The Ontario MK 3 Navy Knife is the one used by the US Navy Seals. The weapon features a stainless steel blade that measures close to seven (7) inches in total length.
Note: The short video [1:41 seconds] contains more information about the special scuba skill 'dealing with fishing line entanglement', especially for beginners.