While lakes and beaches are the go-to spots for many metal detecting enthusiasts, most stick to dry land. Traditional metal detectors just aren’t built for offshore exploration, leaving most to simply imagine what treasures lurking beneath the surface of the water.
Luckily, there are some devices out there to help you scratch that treasure-hunting itch. The best underwater metal detectors allow you to take metal detection technology with you during a dive or snorkeling trip. They’re purpose-built with underwater exploration in mind, ensuring that you can stay safe while you explore.
Underwater metal detectors don’t come cheap. They have some unique submersible technology to enhance performance in underwater conditions. Before you pick the first detector you see, it’s essential to understand how these machines work and what to look for. Take a look at our comparison chart and buying guide below to make a buying decision that you’re confident in.
Top 5 Underwater Metal Detectors 2021
1. Fisher CZ21-8
2. Garrett AT PRO
3. Fisher 1280X-8
4. Garrett Sea Hunter Mark II
5. Minelab Excalibur II 1000 Bundle
6. Whites TDI BeachHunter Extreme
7. TTLIFE Pulse Induction 750 PinPointer
- Top 5 Underwater Metal Detectors 2021
- 1. Fisher CZ21-8 Underwater Metal Detector – Best All-Around Product
- 2. Garrett AT PRO Underwater Metal Detector – Best for Shallow Waters
- 3. Fisher 1280X-8 Underwater All-Purpose Metal Detector – Best for Beginners
- 4. Garrett Sea Hunter Mark II – Best for Working Around Mineral Issues
- 5. Minelab Excalibur II 1000 Bundle – Best Premium Product
- 6. Whites TDI BeachHunter Extreme Waterproof Metal Detector – Best for Comfort
- 7. TTLIFE Pulse Induction 750 Underwater PinPointer – Best Affordable Product
- Best Underwater Metal Detectors Buying Guide
- Types of Technology Used for Underwater Metal Detectors
- Water-Resistant vs Water-Proof Design
- How to Choose the Best Underwater Metal Detector
1. Fisher CZ21-8 Underwater Metal Detector – Best All-Around Product
First things first, this metal detector has some impressive waterproofing features. It can hold up in depths of up to 250 feet! Plus, it has a built-in discrimination system. Things like ground mineralization or saltwater won’t affect its performance. Thanks to the two frequency range options, you can search for a wide range of treasures. Plus, there’s a Target ID system that lets you distinguish between iron and gold without even having to dig anything up.
All in all, this metal detector checks off all the boxes. It’s built for underwater exploration and does well in a wide range of environments. For that alone, it’s well worth your consideration. When you factor in the powerful detection and audio systems, it’s a win-win all around.
2. Garrett AT PRO Underwater Metal Detector – Best for Shallow Waters
One of the highlights of this detector is the audio system. There are two detection modes available. In the professional search mode, you can take advantage of Pro Mode Audio. It’s a dynamic system that lets you hear the unique characteristics of a target. The audio signal is altered based on the size of the object, its distance to the coils, and even the material. With the latter feature, you’re able to quickly ignore trash metals like iron.
While you can’t take this machine on a dive with you, it’s certainly capable of helping you discover some underwater finds. The waterproofing measures taken make it a worthy contender for shallow waters. Check out our comprehensive Garrett AT Pro review.
3. Fisher 1280X-8 Underwater All-Purpose Metal Detector – Best for Beginners
You don’t have to a seasoned professional to use this metal detector. It has a deep-seeking Aquanaut system. Once you turn the detector on, you’re good to go. Aquanaut will automatically make performance adjustments based on the conditions you’re in. You don’t have to fiddle around with settings to start finding treasure. This system will do it all for you down to depths of 250 feet.
Don’t expect this model to provide you with professional-quality results. It’s a simple detector that can help rookie detectors find valuables in the most treacherous places. For that reason, we recommend this model for new users who don’t need a ton of adjustable settings.
4. Garrett Sea Hunter Mark II – Best for Working Around Mineral Issues
The detector is very well designed. It weighs less than four pounds and has a couple of ways to mount it. You can attach it to a hip belt or use the included arm cuff to direct the device where you want it. The machine is also painted bright yellow for enhanced visibility.
From a performance standpoint, this machine is a bit limited. It only does 750 pulses a second. This is quite low compared to some of its competitors. While it does great in briny and mineralized soil, the low frequency could present a problem finding smaller pieces of metal.
Despite its shortcomings, we still recommend this metal detector. The pulse induction technology makes it an excellent choice for rougher environments.
The design of the detector may take some getting used it. Because it’s placed directly on top of the body, the controls can weigh the machine down. Plus, you have to move the device away from the ocean floor to make adjustments.
If that’s not a deal-breaker for you, the metal detector has a lot to offer. The frequency is fully adjustable, and there’s a simple discrimination system built-in. The unit, as a whole, is built tough. It can withstand the pressure of water 300 feet down. Plus, with 12 hours of battery life, you can spend hours down there searching for treasure. What’s not to like?
6. Whites TDI BeachHunter Extreme Waterproof Metal Detector – Best for Comfort
Instead of putting the control panel on the pole of the metal detector, this model uses a separate box that you can mount onto your hip. This keeps the handheld unit light and manageable in any condition.
The control box offers some simple adjustments for sensitivity and frequency. The coil on the bottom of the detector features a dual-zone design. It produces two electromagnetic fields to help you find small and large targets at the same time.
This is a cool metal detector with a lot to offer. This model has you covered whether you’re wading through the shoreline or trekking through muddy lake waters.
7. TTLIFE Pulse Induction 750 Underwater PinPointer – Best Affordable Product
Don’t expect this machine to perform as well as a full-sized model. Despite its good performance capabilities in salt water and mineralized soil, the pulses just aren’t as powerful to do large sweeps for treasure. It’s meant to help you pinpoint items after you already have a general idea of where it is.
All in all, this metal detector is a great tool to have in your arsenal. We recommend that you use it with a larger metal detector to save time and effort during your digs.
Best Underwater Metal Detectors Buying Guide
Ultimately, underwater metal detectors work the same way that on-land varieties do. They rely on the same technology to detect metal buried beneath the substrate. Basically, metal detectors utilize powerful coils that produce an electromagnetic field. The exact way the device does that can vary, but we’ll get into that a bit later.
As you know, metal is an excellent conductor. When those hidden metals are exposed to the electromagnetic field produced by the device, they start to create a field of their own. Your detector will pick up that new electromagnetic current and alert you.
What makes an underwater metal detector unique?
Well, it all comes down to design. Because metal detectors create this electromagnetic field, they’re highly sensitive to water. Water and electricity don’t mix. Having those crucial components come into contact with water can be a recipe for disaster. Not only do you run the risk of getting a nasty shock, but your fancy detection device would be rendered useless.
Manufacturers work around the dangers of water by sealing all of the components from the outside world. They’re fully protected from the water and can operate without any issues.
Why Can’t You Use a Traditional Metal Detector Underwater?
Beyond fundamental flaws in their core design, standard metal detectors just aren’t powerful enough to work well in water. Cheaper devices can’t look past all of the stuff that’s found in lake beds and beach sand.
Let me explain…
Sand and dirt that’s found at the bottom of a body of water are usually highly mineralized. This means that it’s comprised of different types of rocks and metals. In the metal detecting world, ground mineralization can be a huge hassle. Those minerals are ground up so fine that they’re virtually undetectable by the naked eye.
However, that’s not stopping your metal detector from picking them up. Those minerals make the ground highly magnetic overall, which poses a problem when you’re using electromagnetism to find long-lost relics and scraps.
The biggest problem you’ll face with a traditional metal detector in mineralized soil is that you can’t pick up anything. The device will go off constantly, even if there’s nothing substantial nearby.
High-quality underwater metal detectors can look past all of that mineralized soil. Things like filters, pulse detection, and more make the detectors more sensitive while overlooking the stuff you don’t care about.
Types of Technology Used for Underwater Metal Detectors
Metal detectors have evolved quite a bit in the last few decades. The technology powering them has gotten more advanced than ever, paving the way to sensitive underwater models.
While there are a handful of different detection technologies available, two of them have proven to be very effective for underwater use. This includes pulse induction and very low-frequency detection.
Pulse Induction Detection
Pulse Induction metal detectors are the preferred option for underwater use. As the name would suggest, these devices produce many pulses of an electromagnetic field rather than a long and continuous one. Most detectors can do upwards of 100 pulses a second.
These metal detectors rely on those pulses to find objects. After each pulse, a second pulse is sent through the coils. This is referred to as a reflector pulse. Like the first pulse, the reflector pulse collapses in mere milliseconds. That is, however, unless there’s a metal object in the vicinity.
The resulting electromagnetic field from the hidden object causes the reflector pulse to die slower. The metal detector uses that information to determine that there’s something worth digging below.
The cool thing about pulse induction metal detectors is that they’re not affected by ground mineralization too much. They’re highly sensitive and will naturally ignore minerals and salt in the water. Plus, the electromagnetic pulse penetrates deeper into the soil, increasing the odds of finding something.
Very Low Frequency Detection
While they aren’t as powerful as pulse induction machines, very low-frequency metal detectors can work well underwater. They’re one of the most popular types of detectors on the market today.
Also referred to as VLF detectors, these machines produce a constant magnetic field. One coil generates the magnetic field and pushes it into the ground. Once the magnetic field bounces back, it’s picked up by a secondary coil.
If you move the coils over a metal object, the detector will find it by reading the resulting magnetic field. These devices rely on different polarities to detect objects. The magnetic field from the metal object in the soil will be the opposite of the one produced by the detector itself, allowing the device to differentiate the signals.
VLF metal detectors can be a bit finicky when used in tough environments. They don’t perform as well in mineralized soil and tend to have an overall weaker sensitivity. With that said, most VLF devices nowadays are highly customizable. Thanks to an array of adjustment settings, you can fine-tune them to work in your environment and overcome many obstacles that are making your quest more challenging.
Water-Resistant vs Water-Proof Design
There’s a lot of marketing jargon used to describe a product’s performance in wet conditions. While they’re easy to confuse, there’s a huge difference between water resistance and complete waterproofing.
If a metal detector is described as “water-resistant,” that means that it has some protection against moisture. There may be a sealed coil housing or moisture-resistant material. However, it’s important to remember that these devices cannot be fully submerged. They’re made for use around shallow puddles or along a shoreline. A few splashes of water aren’t going to hurt it, but submerging the entire unit into the water will damage it.
Now, a waterproof metal detector is the one you want to go for. It’s fully protected and can be used when diving. The “waterproof” label is rightfully earned through strategic engineering and rigorous testing.
Before you pick the first waterproof model you see, it’s important to take a look at the IP rating. This rating system is used to let you know how much water the device can take.
Some metal detectors can only work in shallow depths of a couple of feet. Thus, they’re more suited for light snorkeling or wading through the water. Typically, these detectors are granted a lower IP rating, such as IPX-4 to IPX-7. If the detectors can be continuously submerged at depths more than a meter, it will be granted a rating of IPX-8.
How to Choose the Best Underwater Metal Detector
Now that you understand the basics of underwater metal detectors let’s dive a bit deeper into the features you need to look for. Not all metal detecting devices are made the same. To ensure that you’re not choosing a product you’ll regret, keep the following things in mind.
1. Water Compatibility
Do you plan on using your new metal detector in freshwater lakes, brackish water, or in the open ocean? It might not seem like it would make a huge difference, but metal detectors perform differently in salty water. Salinity levels are akin to ground mineralization.
Salt can affect the device’s ability to find non-ferrous metals. If the machine is not capable of looking past the salt content, you may find yourself experiencing more false readings.
2. Depth Limitations
As we mentioned earlier, depth and water protection are crucial when it comes to underwater metal detection. Don’t assume that a device can be submerged to great depths just because it’s waterproof. Look at those IP rating to make sure. Sometimes, those waterproofing measures can be damaged due to the pressure of being in deep waters.
3. Coil Size
When you’re choosing the perfect metal detector, there’s a fine balance between portability and coverage. A larger coil will let you scan huge areas very quickly. But, you’ll have to deal with carrying around a cumbersome device while you’re underwater.
4. Frequency Range
Some metal detectors operate on a fixed frequency. Others allow you to adjust the system manually. The latter option is always preferred, as it allows you to search for specific types of metals. For example, metals with low conductivity usually need a higher frequency to find. This includes precious metals like gold or silver.
You can find metal detectors with frequencies as low as 3 kHz up to 100 kHz. Depending on the model, these settings may be fine-tuned with a knob or selected from a couple of predetermined options.
5. Mineralization Filter
Built-in mineralization filters are a must-have for underwater treasure hunting. If you remember from earlier, we said that pulse induction systems did a better job of getting past high mineralization rates. While this may be true, you can still benefit from a filter.
Many models allow you to turn the filter on or off at will. This is great if you plan on using your new gadget in a range of different environments.
6. Control Interface
Next up, you need to think about the overall user experience? Are you a seasoned metal detecting enthusiast, or are you new to the game? If you fall into the former category, you can benefit from getting a feature-rich control panel. Machines with all the bells and whistles make fine-tuning your experience a breeze.
On the other hand, they may be confusing for novice metal detecting hobbyists. In those cases, a simpler machine may be the better choice. They have simple settings and do a great job of explaining what to do at the moment.
7. Audio Support
Most detectors use an audible signal to alert you to the presence of metal nearby. However, there are a few different audio systems available.
The simplest is plain old beeping. A single beep is effective, but it doesn’t provide you with nearly as much information as a ground-balanced audio system. These systems produce high-pitched noise that is directly related to the strength of the electromagnetic field. Thus, a louder or higher-pitched tone means that the object is relatively close.
Generally, more detailed audio systems are better for underwater use. There are many variables underwater. The last thing you want to be doing is trying to guess where the hidden object is.
Finally, there’s comfort. This is a big thing to think about. This hobby can get dangerous quickly when you factor in all of the potential hazards of being underwater.
A comfortable metal detector that’s lightweight and portable is must-have. While clunky metal detectors are fine for land-based searches, they can weigh you down in the water. Plus, they make it harder for you to swim to safety if an issue occurs.
Look out for devices that are small and easy to hold with one hand. Sturdy arm supports, wrist straps, and other security features are always recommended.
There’s no shortage of high-quality underwater metal detectors out there. Finding the right one is about understanding the unique challenges you’ll face when searching in water conditions.
By choosing a protected metal detector, you can discover long-lost treasures that most metal detecting hobbyists could never find. Check out one of our recommended picks to see what you can find!