Best 5 Underwater Metal Detector

metal detector

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How many times have you wished you had an underwater metal detector in hand when you went down for a dive? Have you ever been curious of what might be buried under the sea or lake floor? Metal detecting is a fascinating hobby that can yield incredible treasures. Old coins, diamond rings, and gold nuggets have all been found underwater. Some experts claim water, especially the ocean floor, is the last unexplored frontier on Earth.

Here we will present some of the most frequently asked questions about using an underwater metal detector and move on to review the best 5 underwater metal detectors for you to use on your next dive.

Comparison Table

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Underwater Metal Detectors FAQs

1. What Is an Underwater Metal Detector?

A metal detector is a specialty electronic device that creates a signal in the presence of metal. Traditionally, people use metal detectors to search for buried metal on land. An underwater metal detector is used to locate metals buried underwater or obscured by watery landscapes.

2. How Do I Use an Underwater Metal Detectors?

Using a metal detector is a simple yet skilled process requiring the searcher to hold the device and swing it over the ground. Guiding the device “low and slow” over the ground without ever touching the top is the method touted by metal detecting experts. 

3. What Makes an Underwater Metal Detector Work?

Each metal detecting device has slightly different mechanics. In general, metal detectors use the properties of electromagnetism to notify you when metal is below your feet.

The device uses a combination of a battery, transmitter circuits, and a transmitter coil to activate the magnetic field. When metal meets this field, the metal produces an electrical current. This electrical current shoots up the device and activates the device’s alarm signal.

4. Why Would I Use an Underwater Metal Detector?

The better question might be why wouldn’t you use an underwater metal detector? Every day, professional and amateur underwater divers are using metal detectors to discover buried treasure. With treasure hunting underwater, you have to play in order to win. Some items you might recover from using an underwater metal detector find are:

  • Gold
  • Silver
  • Bronze
  • Iron
  • Nickel
  • Copper
  • Brass
  • Lead
  • Jewelry with or without diamonds or other gems
  • Watches
  • Rings
  • Necklaces
  • Coins (rare or modern)
  • Religious regalia

5. Will the Device Detect All Metal or Can I Select Which Metal to Look For?

Most metal detectors for land, water, or both come with functions to help you locate specific types of metals.

Pinpoint mode or discrimination mode on a metal detector allows you to decide which metals to detect. These modes work to exclude certain materials from your search. You can often switch between specific metals and an all-metal mode.

Sensitivity settings adjust how the magnetic field in your device reacts to metal. Adjusting the sensitivity setting can help you navigate through heavily mineralized ground regions to differentiate materials.

6. How Will I Know I’ve Found Metal If I’m Underwater?

Just like metal detectors exclusively designed for land use, underwater metal detectors function with headphones and an audio output jack. Specialty headphones are required for underwater use.

When the device has picked up a signal from metal in the water, you will hear a tone in the headphones. Tones will vary depending on the device. Always read the provided instruction manual to understand the meaning of the tones your device makes.

Some underwater metal detectors also come equipped with flashing light functions that can help signal the detection of metal although this is not standard.

7. What Are the Types of Underwater Metal Detectors?

There are two types of metal detectors suitable for underwater use. These two types are pulse induction (PI) metal detectors and very low frequency (VLF) metal detectors. Both have their own perks.

Pulse Induction

PI devices are pricier devices but are best used in saltwater or when the water is very deep. PI metal detectors can detect metal, including gold, from extreme depths.

Very Low Frequency

VLF devices are the preferred choice for amateurs and hobbyists. These devices are lighter in weight and lighter on the wallet. Opt for a VLF metal detector for searching in freshwater sources.

8. Is It Legal To Use an Underwater Metal Detector?

Metal detecting is legal for the most part, but there are some laws you should know. There are laws in place prohibiting treasure hunting on federal land, state-owned land, local land, archaeological sites, and private property. Check the specific rules of your state before collecting embarking a treasure dive.

9. Where Can You Buy Underwater Metal Detectors?

Underwater metal detectors are available from many online retailers. Amazon is a great source for buying a device because they provide many options in one place along with reviews from buyers who have already used the product.

How We Reviewed

We’ve reviewed the best underwater metal detectors to help you decide which device is best for you. The structure of each review contains information about product features, pros and cons of each device, pricing, where to buy, and warranty information. All the underwater metal detectors we reviewed are high-quality and well-known in metal detecting circles. We objectively looked at product specs and performance to bring you the best underwater metal detectors available today.

Overall Price Range of Underwater Metal Detectors

Underwater metal detectors come with varying price tags. General prices can range from $150.00 to over $2,000.00. The highest price on our list is around $1,500.00 dollars, while the lowest price on our list comes in a little lower than $600.00. More expensive waterproof metal detectors sometimes come with more features, options, and extras than less expensive models. This isn’t always the case. This review focusses on quality rather than pricing. As you will see, the best underwater metal detectors are in the mid-range for pricing.

​What We Reviewed

  • Minelab Excalibur II
  • Garrett Sea Hunter MK-II
  • Garrett Infinium LS
  • Tesoro Tiger Shark
  • Garrett AT Pro

Minelab Excalibur II

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The Minelab Excalibur II is a waterproof metal detector with modes to pinpoint specific metal types. It weighs around five pounds. It comes with two length options—the standard shaft reaches 45 to 48 inches while the dive shaft extends from 32 to 36 inches. Minelab Excalibur II uses a NiMH battery pack with a 13 volt 1000 mAh for up to 19 hours of continuous battery use.

It comes with BBS software technology, a variety of frequencies, a 10 inch round Double-D hard-wired coil, and hard-wired Koss 8 headphones. For ground balance, the Minelab Excalibur II futures auto ground rejection, manual and automatic sensitivity adjustment, and adjustable threshold functioning.


  • For land or water use
  • Can dive up to 200 feet
  • High visibility fluorescent lighting 
  • Comes with headphones
  • Long battery life


  • The price 
  • Knobs sometimes strip
  • May experience battery problems

Where to Buy

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Warranty for the Minelab Excalibur II is one year for the control box and coil.

Garrett Sea Hunter MK-II

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The Garrett Sea Hunter MK-II is a PI metal detector made for all water sources including oceans, lakes, and beaches. It comes with advance Pulse Discrimination capabilities, the Garrett Discrete Trash Elimination mode, and four configuration modes.

The device has an adjustable length ranging from 28 inches to 52 inches. Garrett Sea Hunter MK-II weighs in at six pounds. It uses eight AA batteries. Garrett Sea Hunter MK-II has a submersible headphone jack, adjustable audio threshold, and a deep seeking mode for locating all types of metal in deep waters. It can safely reach depths of up to 200 feet under water.


  • Suitable for saltwater
  • Functions on land and in water
  • Picks up metal buried deeply buried metals


  • Doesn’t come with headphones
  • Shaft is somewhat flimsy
  • Discrimination function isn’t strong

Where to Buy

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The Garrett Sea Hunter MK-II comes with a limited one-year parts and labor warranty.

Garrett Infinium LS

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The Garrett Infinium LS land and sea PI metal detector is a versatile device that allows you to search 200 feet below the surface or on land. It comes with an adjustable length spanning from 28 inches to 52 inches. It weighs five and a half pounds. It uses eight AA batteries. Alkaline batteries are included.

Garrett Infinium LS offers 96 different frequencies and adjustable detection frequencies with up to 730 pulses per second. It features a salt elimination mode, ground balance, auto ground tracking, surface mount PC Board Technology on a hip mount control box.


  • Works well in saltwater and freshwater
  • Locates deeply buried metal materials 
  • Functions well in highly mineralized environments
  • Simple to operate


  • Discontinued model/limited availability 
  • Discriminate control is limited 
  • Audio tones are not standard for detecting certain metals

Where to Buy

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Because this product was discontinued, make sure to check the warranty from the source you buy the Garrett Infinium LS from. Different retailers offer different warranties for products. Always look for at least a one-year warranty for any underwater metal detector.

Tesoro Tiger Shark

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The Tesoro Tiger Shark underwater metal detector is a dual-functioning land and water device with hard-wired, round open-centered concentric coils that measure from 8 to 10.5 inches in diameter. It produces an audio frequency of 270 hertz and operates on 12.5 kilohertz. The Tesoro Tiger Shark is listed to weigh between under 4.5 up to 6.35 pounds.

The Tesoro Tiger Shark can plunge into water up to 200 feet. The device operates on 8 AA disposable batteries. The Tesoro Tiger Shark underwater metal detector is designed to use ground balance to avoid picking up minerals in the ground surface. It comes equipped with two easy-to-use activation modes. The SALT mode for water searching and the NORM mode for land.


  • Lightweight
  • Lifetime warranty
  • Waterproof headphones included
  • Good value for the price 


  • Limited frequency output
  • Doesn’t use rechargeable batteries
  • Hard-wired search coil

Where to Buy

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Tesoro offers a lifetime warranty for the Tesoro Tiger Shark when it purchased from authorized dealers of Tesoro products. Check individual warranty information from the retailer you purchase your Tesoro Tiger Shark from for more information. 

​Garrett AT Pro

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The Garrett AT Pro is Garrett’s newest professional quality underwater and all-terrain metal detector. it comes with professional audio, high resolution discrimination, digital targeting, and 15 kilohertz location frequency. The device reaches 43 to 56 inches in length and weights slightly over three pounds.

There are six modes included in the Garrett AT Pro device along with eight sensitivity adjustments. Locating specific metals is made simple with the device’s built-in electronic pinpointing method. The Garrett AT Pro runs on 4 AA batteries.


  • Exceptionally lightweight
  • Many setting options
  • Long warranty
  • Professional audio quality
  • Works in fresh and saltwater


  • Doesn’t use rechargeable batteries
  • Doesn’t come with waterproof headphones
  • Single frequency

Where to Buy

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The Garrett AT Pro comes with a two-year limited parts and labor warranty.

The Verdict

All the underwater metal detectors we reviewed have merit. Overall we find that the Tesoro Tiger Shark is the best device for underwater exploration on a budget. It offers the right amount of features and is easy to use. The manufacturer’s lifetime warranty is tough to beat.For those with a serious metal detecting hobby, we recommend the Garrett AT Pro. The feature selection is comparable to devices sold at a much higher price point. As a treasure hunting diver, it’s ultimately up to you to decide which device will best serve your purposes and price range.

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