Garrett Sea Hunter Mark II Review

Very Good
Metal Detector
  • Country USA
  • Released -
  • Warranty 2 year
  • Additional
  • Headphones included

Best for

  • Beach
  • Underwater

garrett sea hunter mark ii preview

Garrett Sea Hunter Mark II metal detector was designed specifically for the underwater search. It is on the more expensive side, and also has a bunch of complicated settings to tune, but the user experience is excellent, while the search efficiency is next to unbelievable. The main point behind Sea Hunter Mark II is to make deep underwater detecting productive and efficient, at the same time bothering the user with only a few settings.

To find out about the main pros and cons, features, and other nuances, check this Garrett Sea Hunter Mark II reviews.

Rating Explanations
All Purpose
Key Features
Easy to Use
Reviewed by
Michael Moore
  • waterproof up to 200 feet
  • hip mount available
  • submersible headphones included
  • one additional compatible search coil
  • user-friendly and easy to tune underwater
  • no Pinpoint mode
  • no vibration
  • no Lost Alert
  • powered by 8 AA batteries
  • heavy
  • expensive
  • Technology: PI
  • Number of frequencies: 22
  • Frequencies: 0.75 kHz
  • Search Coil: 8"
  • Search Coil Type: Mono
  • Waterproof: Up to 200 feet
  • Updatable Software: No
  • VDI (Target ID): No
  • Search Modes: 3
  • Search Mode Types: Discrete, Non-Motion All Metal, Standard
  • Ground Balance: No
  • Pinpoint Mode: No
  • Audio Tones: 1
  • Batteries: 8 AA batteries required
  • Length (min-max): 28"-52"
  • Weight:5.07 lb
  • Warranty: 2 years

Garrett Sea Hunter Mark II Key Features

Pulse Induction Technology

Allows to spot all targets that get magnetized by the electromagnetic field created with short impulses sent into the coil.

22 Operating Frequencies

Incredible range of opportunities for successful detecting, which is especially valuable in harsh underwater conditions.

Mono Coil

While such configuration requires more overlapping, monoloop coils can provide even better depth of reach that DD shaped coils.

High Level of Discrimination

Irreplaceable feature for treasure hunting in salty and highly mineralized waters.


Up to 200 feet is an impressive level of waterproofness that allows a wide range of underwater locations for exploration.

Three Parts Shaft

Easy and safe to mount on hip or chest for comfortable diving and freedom of movement underwater.

Garrett Sea Hunter Mark II Overview

garrett sea hunter mark ii overview

Sea Hunter Mark II has the reputation of one of the best underwater metal detectors in the niche. It is handy, durable, easy to use (although a certain learning curve is present!), and provides an excellent balancing to avoid false signals caused by salty water.

Sea Hunter Mark II by Garrett is a combination of sturdy hardware able to withstand the punishment, and flexible software offering enough features and functions for productive search. One of the best things about Sea Hunter Mark II, though, is that it has a simple, almost primitive Control Box and few settings to bother with. This is done to minimize complications underwater when tuning the machine.

Control Box

garrett sea hunter mark ii control box

Since the machine is submersible, the control panel has no LCD display – anyways it is unlikely to be much useful underwater. Instead, the control panel has Minimum and Maximum Threshold setting, Elimination and Trash Elimination, Headphones connector,  and Power. The good news is that the controls are easy to manipulate; even under poor visibility conditions, the user can manage the controls more or less productively, checking the results by audio signal.

Search Modes

Sea Hunter Mark II is kinda special, so it does not have those standard search modes one could expect. Moreover, such standard modes would have been useless in the conditions under which Mark is created to operate. Instead, there are two special search modes that experts will definitely take advantage of.

Standard Trash Elimination

This search mode is similar to other pulse induction metal detectors. In this mode, the background audio threshold remains continuous and responding to variations of the targets’ response. Smaller and deeper targets give smaller signals, while bigger and closer targets give loud, clean signals.

Discrete Trash Elimination

This search mode is exclusive for Sea Hunter Mark II. It works more like in many motion types of detectors - the background audio remains continuous, but when the potential target is detected, the machine gives a sharp clear sound.

Garrett Sea Hunter Mark II Features

Sea Hunter Mark II is one of those machines which are very unique and created for a narrow sub niche of metal detecting. This metal detector has a bunch of features really crucial for deep diving and effective underwater operation, but at the same time it has no additional fancy features (simply because they are useless 200 feet underwater!), so it may seem that Sea Hunter Mark II is not very cool. But in fact, it is very cool; just check out the list of features in it:

Garrett Sea Hunter Mark II Coils

garrett sea hunter mark ii coil

Sea Hunter Mark II is equipped with a small 8 inches PROformance Mono search coil. Mono type plus round shape of the search coil make it more focused and reaching greater depth. The search coil is comparatively small, but it is handy and easy to manipulate underwater.

There is an additional compatible coil, which is bigger; the 10×14 inches PROformance Mono search coil will scan wider areas faster, while its elliptical shape makes it more versatile and flexible in performance.

Garrett Sea Hunter Mark II Settings

Sea Hunter Mark II is complicated in technology, but pretty primitive in mastering the settings. You will cope with settings and tuning after reading the manual and exercising with the metal detector for an hour or two. In fact, the settings were organized and created in a way to make it as simple and comprehensive for the user as possible. The reason is obvious – when metal detecting 200 feet underwater, you can’t stop, drop the machine, pull out the manual (or your smartphone) to double-check the settings you can’t recall. Swimming back and forth is not an option, too. So, the settings are simple, comprehensive, easy to manage, and therefore there are no particular nuances to discuss but one.

Elimination is the feature that may require a bit more attention than other features. Depending on the goals you expect to find, you may want to keep the elimination as low as possible, allowing you to spot most of the metals. In some cases, zero elimination is what works best. While detecting all kinds of metal trash is not fun, zero or low Garrett Sea Hunter Mark II discriminationwill enable you to notice other, potentially valuable items you might have not expected at all.

Garrett Sea Hunter Mark II Problems

Sea Hunter Mark II is a unique product in the niche, and in many cases, there is no other metal detector to substitute it. However, Mark II is not a new model, and there is a list of problems many users will immediately notice.

The first problem is that the machine is not recent, and its technologies are a bit outdated, but there is no option for online software update, so this problem cannot be solved. Perhaps a slight update could fix small bugs or improve some features, making Sea Hunter Mark II more up-to-date, for it to hold its position for a few more years.

Another problem is no Lost Alert. While this is not a big deal for many cases, we still believe there should be a lost alert for a metal detector that can be lost on the Garrett Sea Hunter Mark II depth of 200 feet. While the control box can be mounted on the hip, not everyone uses this option, and losing an expensive machine somewhere in the muddy waters is not fun.

Tips & Tricks for Garrett Sea Hunter Mark II Users

garrett sea hunter mark ii user

When deep diving with a metal detector, one of the problems and dangers a treasure hunter faces is currents and tide activity. Always research the weather forecast and wind conditions, explore the currents, including underwater or seasonal currents, and watch out for the tide activity. Besides watching all those things for the sake of your own safety, you may also want to check them out for more productivity. The point is, storms and tides often unearth previously unnoticed treasures, can drag things to shallow places from deeper waters, and make totally unproductive locations into extremely promising. So, the bottom line is avoid storms, but go and search after storms.

When you dig underwater, the conditions are even more unfavourable then when you dig on land. Since Mark II is a PI detector, you may encounter certain issues with small iron debris and trash. However, one smart move is to attach a magnet to your digging tool; the magnet will attract the iron trash, while you will be able to search for treasure finds.

Garrett Sea Hunter Mark II Accessories

There are few compatible accessories for Sea Hunter Mark II but the search coil and the submersible headphones. Most underwater treasures do not require digging, and as for Pinpointer, many will not operate at depth available for Mark II. So, the only extra accessories you may want to consider are a hand scoop for shallow sand digging if you hunt down treasures on clean seabed, or a trowel if you happen to search on clay or gravel. However, honestly Sea Hunter Mark II is more fit for wreck exploration rather than digging the mud.

Garrett Sea Hunter Mark II Kit

garrett sea hunter mark ii kit

The basic package includes:

If you want other items included, check out your local retailer or big online platforms. Most retailers create their own bundles and packages with different combinations of additional accessories inside. This way, you can get needed accessories with a small discount.

Garrett Sea Hunter Mark II Manual

To find out more about all settings and functions of Garrett Sea Hunter Mark II underwater metal detector, check out the user’s manual. If you consider buying this machine, reading the manual beforehand is crucial, to make sure this metal detector meets your needs.

Download Garrett Sea Hunter Mark II User’s Manual


How to pinpoint the target without Pinpoint mode and without hand-held pinpointer?

If you need to locate the suggested target more accurately underwater, and obviously you cannot use the Pinpointer tool, and there is no Pinpoint mode in Sea Hunter Mark II, you can use one of the two swiping techniques. The first technique is to swipe the search coil in small narrow steady swipes over the target, and then slowly pull the coil closer to you. When the signal starts to faint, it means the target is right under the tip of the search coil. Another technique which is probably more handy for underwater Garrett Sea Hunter Mark II beach detecting is sweeping the search coil from side to side over the target. When the signal faints it means you reach the edge of the target in the sand. Therefore, you will be able to dig it out more accurately.


While deep underwater detecting is one of the most complicated sub niches of hobby metal detecting, and choosing the right equipment is always challenging, Garrett Sea Hunter Mark II seems to be one of the best options. It is powerful and efficient, and sturdy enough to bear the pressure of the environment. And yet, settings and Garrett Sea Hunter Mark II specs are both comprehensive enough for the user to master quickly, and also simple enough to be manageable on great depth, where delays or confusion are inadmissible.


Garrett Sea Hunter Mark II Perfect for underwater metal detecting

3 Main Competitors

Minelab Excalibur II One of the best for underwater detecting

Fisher CZ 21

Fisher CZ-21 Great underwater detector for a good price

Minelab CTX 3030 The most functionality detector for coins and relics


Michael Moore

Hi detectorists! I’m Michael Moore, founder of this website, and a dedicated treasure hunter since 2013. If you want to be posted about the most recent news and updates in metal detecting, releases, and trends, subscribe!

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