In this guide we’ll take a look at the best underwater metal detectors.
We’ve compared water resistance, performance in salt water, pulse induction and operating frequency to give you our top recommendations.
What Is The Best Underwater Metal Detector?
More Detailed Underwater Metal Detector Reviews
In our opinion, the Fisher CZ21-8 is the best underwater metal detector on the market.
It’s a submersible pulse induction metal detector that goes a whopping 250 feet deep.
If you’re a scuba diver this water machine is a great choice for hunting out the tiniest targets in saltwater.
The control box is easy to use. It has a volume control that can be used to boost audio on weaker signals from potential deep targets.
This Fisher model has a discrimination mode with seven-settings to filter out your metal choices, although many users tend to pick auto-tune which turns it into an all metal mode with deeper penetration but no discrimination.
It also has adjustable sensitivity – the higher the sensitivity the more signals you’ll get, and adjustable the ground balance.
With waterproof headphones, there are three tones that beep low for iron, a medium tone for foil and small gold, and a high tone for coins and jewellery.
The Fisher CZ21-8 is 12 x 6 x 21 inches and weighs 5.3 lbs. Like most PI machines it’s heavier than a VLF detector, but it’ll get deeper into the seabed and ignore all the minerals for you.
- Easy to use
- Submersible up to 250 feet
- Pulse Induction
- Adjustable ground balance if you want it
- It’s pretty heavy
- Not so great on land because of the PI reduced discrimination
The Tesoro’s Sand Shark is a great underwater metal detector for the money, and yet a simple beast! It’s a pulse induction machine so you can pick it up and get wet without any fiddling around.
PI machines don’t have much if anything in the way of ground balancing so you won’t need to spend ages adjusting the controls. PI just deals with high mineralization and lets you enjoy your hobby.
The Sand Shark’s depth capacity is a massive 200 feet making it the best waterproof metal detector too! It’s perfect for snorkelling and scuba divers.
I said it was a simple machine and here’s why. The Sand Shark has two control modes. The modes are VCO and Normal (which is search for all metal)
VCO stands for Voltage Controlled Oscillator. This mode increases in pitch and tone as you approach targets. VCO mode is great for pinpointing the target in shifting tidal sands.
Normal ‘all metal’ mode will increase in volume as you approach a target but the tone remains the same. Which you choose depends entirely on your preference.
Control the pulse induction width by turning a simple knob (great for underwater slow-motion hand movements).
Turn it up for greater sensitivity – perhaps you’ve found a target and want to see if there’s something more a bit deeper beneath it, or if there are small pieces scattered around.
All the controls are simply displayed on the large easy-to-use box, and it has a super fast microprocessor which is great news beneath the waves because you won’t want to be hanging around for a re-set there.
The Sand Shark measures 21.1 x 11.5 x 4.7 inches, weighs less than 4.5 lbs. And you’ll need 8 AA batteries to power her up.
This is a great bit of kit and one of the easiest to use in saltwater conditions. It’s the cheapest PI machine around and comes highly recommended.
Overall, a great pulse detection machine that’s easy to use and very popular with underwater enthusiasts. If you’re looking to graduate to a specific beach metal detector, want to hit the wet sand, or go under the surface snap up this shark.
- Great depth and sensitivity
- Waterproof to 200 feet
- Great price
- Pulse induction
- Not great for discrimination on land
If you want one detector that searches land and sea the Garrett AT Pro is the best choice.
The Garrett AT Pro (that’s AT for all-terrain) has a large search coil and the detector is entirely waterproof to ten feet. It’s a great size that covers plenty of terrains but still catches the small targets.
The AT Pro has superb automatic or manual ground balancing which is essential in VLF machine that can handle saltwater and high mineralization, plus the super fast recovery time means you aren’t standing around bored whilst someone else finds the gold.
It works on a 15kHz frequency to find the small stuff with the 0-99 target scale ID to indicate what’s beneath. Then the continuous coin depth indicator tells you how far to dig.
If it’s iron trash the high-res iron will tell you so. Basically, the Garrett AT does the job for you!
The AT Pro is sold with ProPointer AT which is better known as the Garrett Carrot.
It’s a bright orange waterproof pinpointer that’s also waterproof to ten feet locates the exact position of your find. It’s invaluable underwater or in moving tidal sands and only weighs 6.5 oz.
The Garrett AT Pro measures 21.3 x 14.4 x 8.7 inches and weighs only 3.03lbs. You’ll need 4 AA batteries to light her up.
The machine has loads of features. It’s one of the best around for land and water detection.
- Large search coil
- Waterproof to ten feet
- The Garrett Carrot is invaluable
- All-terrain so you only need one detector
- Better suited to experienced metal detectorists
The Garrett ATX is another top-class machine in Garrett’s arsenal. It’s their pulse induction machine whereas the AT PRO above is VLF. This means it fares much better in salt water.
The ATX has a large 10 x 12-inch search coil that picks up tiny finds without slowing you down.
The large LED screen is basic with no frills. The indicators simply show the signal strength of your target and your current settings.
I like it that way – especially the raised buttons you can feel in water with frozen fingers – simple is what you need when you’re in the water.
You can adjust the ATX discrimination to target a variety of metal on all terrains and you can fiddle with the four settings as much as you want to get it just right.
If you’re more of a getup and go person then leave the default setting and it’ll adjust itself to target the treasure.
It has a quick iron check feature and an auto function that minimizes interference, and if you want to you can adjust the volume control so that large signals don’t drown out the small ones that might indicate something buried deep.
The ATX is adjustable from 20 inches to 68 inches and it weighs 5lbs. You’ll need 8 AA rechargeable batteries to power it up.
- Looks awesome
- Fantastic sensitivity settings
- Provides simultaneous detection on numerous targets
- Waterproof up to 10 feet
- It is expensive
- It’s quite heavy
The Fisher Pulse 8X is a top of the range underwater metal detector for serious detectorists.
It’s pricey but if you want to find the goods this will give you the best chance – it’s used by the military, commercial divers and law enforcement.
This machine has heavy-duty construction and up to 6 feet detection range on land and in salt water – that’ll take some beating.
The pulse detection isn’t affected by highly mineralized salt water or black sands, but it still has great sensitivity to metals. Switch the sensitivity to low, medium, or high to pinpoint your chosen metals and that’s it – so simple to use.
A large visual readout indicates a target and the audio pings too, so you won’t miss what’s hiding beneath the soil, sand, waves or rocks.
A recent improvement in technology means that underwater metal detectors can now be equipped with waterproof headphones that block out background noise. In the past detectorists had to rely on needle readouts.
If you want to its possible to change the coils to a smaller or larger size.
A handy, if not essential, feature of the Pulse 8 is that it has slightly negative buoyancy – so feel free to dig up a target without your machine floating off in the current.
This professional underwater metal detector has a rechargeable 9-volt battery that reviewers say will last all day long.
- 200 feet depth
- Commercial grade
- Sensitivity setting to help ignore the trash
- It’s a PI machine so not so great for land detection
Advice for Choosing the Right Underwater Metal Detector
Hunting for treasure beneath the water is exciting. When the beaches and lakes are crowded with detectorists heading into the water to clean up after the summertime tourists is an attractive and often lucrative option.
Is your metal detector up to the job?
To hunt for underwater treasures your machine needs to be waterproof and if you’re heading to the ocean it must be able to handle highly mineralized saltwater conditions.
You’ll need a specialist underwater metal detector if you want to scan the seabed for coins, jewellery and sunken galleons.
Pulse Inductions vs Very Low Frequency
There are two types of metal detectors that suit underwater salty conditions.
- Pulse Induction (PI)
- Very Low Frequency (VLF)
Here’s the difference:
Pulse induction (PI) works by shooting frequent bursts of electronic pulses into the ground and receiving back a signal if they hit something metal.
They are better for saltwater as they can deal with high mineralization, but they can’t discriminate as well as VLF machines.
This means you’ll pick up everything including iron and trash unless you buy a pricey top of the range machine with sensitivity.
Very Low-Frequency machines work by detecting on a low frequency, and their technology means you have a better ability to discriminate.
A good ground balancing VLF machine will ignore mineralized soil and you’ll be able to pick out the treasure rather than a rusty nail.
So which do you want?
In the blue corner: VLF machines are more versatile for sure. They can be used on land, saltwater and freshwater with good discrimination on mineralized ground. They are often lighter than pulse machines too.
In the red corner: A pulse induction machine finds deeper, smaller objects than VLF detectors and they’re programmed to ignore ground minerals. There’s no adjustment -just grab and go.
If you want to primarily hunt underwater in salty conditions I’d recommend a PI machine. If it’s freshwater you want then feel free to choose whichever you like the most.
Is Your Metal Detector Entirely Waterproof?
Double-check before you commit the cash because some machines have a waterproof coil but the control box is not watertight.
Dropping it in water or getting caught out by a rogue wave can destroy your hard-earned machine in seconds.
If you’re hunting in water its best to have a specific underwater metal detector which is entirely waterproof.
When To Go Metal Detecting Under Water
Scuba divers head out all year round but if you are planning to snorkel with your underwater metal detector or splash in the surf then the best time to find something exciting is during summer.
This is when tourists and beachgoers enter the water – and lose their jewelry.
Summer waters are also warmer than winter ones so you can hunt for a longer period of time.
Of course, you can metal detect in the winter, but you’ll probably need a wetsuit and a very close eye on the weather. Don’t head out in stormy conditions.
Daylight hours are the best time to metal detect underwater because you can see what you’re doing and its generally safer all round.
Know Your Current From Your Raisin
If you’re getting into the water ensure you know exactly when and where the tide is heading.
Understanding the tide is an essential requirement if you’ll be spending time on the beach. Too many people have got into difficulties when the tide has caught them out – please be careful.
Knowing the tide brings another benefit too – you can find targets quickly and more easily.
This is because sand moves in the tide’s direction and this gives you the opportunity to see more of the seabed. Fighting the tide is exhausting and you’ll miss targets. Go with the flow.
Accessories are not essential, but they certainly make a more pleasant experience. Here are a few suggestions to put on your Christmas list.
Waves are noisy and the wind can drown out faint target signals. If you’re heading beneath the surface then waterproof headphones are essential.
A long steel trowel
These help you dig at the rocky ocean floor and move sand faster than scrambling with your hands. If you’re snorkelling or walking along the surf you can stay standing while you uncover a target.
Some of these underwater metal detectors are heavy. You might not think that 5 pounds are a lot but after you’ve been swaying them side-to-side for a few hours they’ll feel like a mountain.
Wave action will grab at the detector and drag it around too. A chest harness takes the weight from your arms and makes water exploration safer because you can steady yourself and maintain balance.
A mesh pouch is important if you are snorkelling or scuba diving. You’ll need some to put all those finds!
The Ocean Is Calling
If you enjoy metal detecting it’s more than likely you’ll end up in the surf, if not deeper.
Most detectorists start on the beach or lakeside and end up drawn to the wet sand, and then the water itself. There are plenty of finds there and if you have the right equipment plus some patience you‘ll uncover them.
I’d really recommend an getting yourself the best underwater metal detector if you are spending lots of time in or near the water. Even if you don’t want to submerge the whole machine accidents happen and these detectors are not cheap.
Happy Hunting fellow detectorists – and good gold to you.