"Waterproof" means two completely different things on a spec sheet, and mixing them up is the single most expensive mistake in this category. A waterproof coil means you can swing in wet grass, light rain and a few inches of shallow water - the search coil is sealed, but the control box on the shaft is not. A fully submersible detector means the whole machine, control box included, can go underwater. If you plan to wade, hunt the surf line or dive, only the second kind will do. Nearly every beginner detector sold has a waterproof coil. Only a handful are truly submersible, and those are the three below.
Waterproof coil vs fully submersible: the distinction that matters
This is the one number to check before anything else. Most entry-level machines - the Garrett ACE series, the Fisher F22, the Bounty Hunter models - carry a waterproof coil rating. That covers rain, dewy grass and dipping the coil into shallow water. It does not mean you can put the control box under. Drop one of those in the surf and you have a dead detector.
A fully submersible machine seals the entire unit. You can wade in up to the manufacturer's depth rating, hold it underwater to check a signal, or hunt a river bed without a second thought. The trade is small: submersible machines usually cost a little more and are built a bit heavier, but if water is your target ground, there is no substitute.
| Detector | Water rating | Can the control box go under? |
|---|---|---|
| Nokta Simplex Ultra | Fully submersible | Yes |
| Minelab Vanquish 360 | Fully submersible | Yes |
| Nokta Simplex Lite | Fully submersible | Yes |
| Garrett ACE 300 / 400 | Waterproof coil | No |
| Fisher F22 | Weatherproof | No |
| Bounty Hunter Land Ranger Pro | Waterproof coil | No |
Why wet salt sand is the real test
Waterproofing gets you into the water. Staying stable once you are there is a separate problem, and it is where single-frequency machines struggle. Wet salt sand is highly conductive and mineralised - a single-frequency detector reads it as one giant target, loses depth and starts chattering. This is exactly the ground where lost rings and jewellery end up, so it is the ground that matters most.
Multi-frequency is the answer, and it is the reason the Minelab Vanquish 360 earns its place here despite not being purpose-built for water the way the Nokta machines are. It transmits several frequencies at once and cancels out the salt interference, so it holds depth on a wet beach where a single-frequency detector would be useless. If your main target is the swimming beach and the wet strip at the water's edge, that stability is worth as much as the submersible seal.
How we ranked them
The Nokta Simplex Ultra sits first because it is a genuine water machine that also works everywhere else - fully submersible, simple to learn, and stable on wet ground. The Vanquish 360 is second and would be first for someone who hunts almost entirely on salt beaches, because multi-frequency beats everything else on that specific ground. The Simplex Lite is the budget entry: fully submersible for noticeably less money, with fewer settings, which is the right pick if waterproofing is the one feature you cannot compromise on but the budget is tight.
A machine rated for five metres of submersion tells you how deep the housing survives, not how deep it detects targets. Those are unrelated numbers. For how far any detector actually finds a coin or ring, see our guide on how deep a metal detector can detect - the honest answer is far shallower than the box implies.
What we would tell a beginner
If you know you will spend real time in or beside water - wading, surf hunting, river beds - buy submersible from the start. Retrofitting is impossible; you cannot make a non-submersible machine safe underwater. If you only ever dip a coil in shallow water and mostly detect dry land, a good all-rounder with a waterproof coil saves you money. And if beaches are your thing, weight the decision towards multi-frequency, because the salt is a bigger obstacle than the water itself.
Beaches are also where most beginners find their first gold, because lost rings collect in wet sand. The overlap between water hunting and jewellery hunting is almost total - so it is worth reading our take on the best metal detectors for gold alongside this list, and comparing the two top picks in our Vanquish 360 vs Simplex Ultra breakdown before you spend.