Seestern SUB600T V3 Review: The 200m Diver That Punches Well Above Its Price

Short answer: the Seestern SUB600T V3 is an automatic dive watch running a genuine Seiko NH35A movement, with a sapphire crystal, ceramic bezel and 200m water resistance. Its standout features are an unusually tight bezel action and a fully lumed date wheel that is rare at any price. The movement is reliable rather than chronometer-accurate. For the money, very little competes with it.

There is a particular kind of watch that turns up every few years and quietly embarrasses everything around it. The Seestern SUB600T is one of them. Sapphire crystal, ceramic bezel, a genuine Seiko movement and 200 metres of water resistance — a specification that would have cost four figures fifteen years ago.

The obvious question is what has been left out. The honest answer is: less than you would expect, and not the parts that matter.

What is the Seestern SUB600T a homage to?

Most people assume any steel diver with a rotating bezel is chasing the Rolex Submariner. This one isn't.

The SUB600T takes its cues from the DOXA SUB 300T, the 1960s cushion-cased diver worn by Jacques Cousteau's team and later immortalised in Clive Cussler's novels. The clues are in plain sight once you know: the broad cushion case, the bezel treatment, and the name itself — DOXA's SUB 300T became Seestern's SUB 600T.

That matters commercially as well as historically. DOXA homages are far rarer than Submariner homages. Where the affordable market is saturated with black-dial, black-bezel Sub clones, the SUB600T arrives in orange, teal, yellow and turquoise — colours that read as deliberate rather than derivative. If you want a dive watch that doesn't look like everyone else's, this is one of very few affordable routes to one.

Is the Seiko NH35 a good movement?

Inside is the Seiko NH35A, and it deserves more respect than it usually gets.

Twenty-four jewels, 21,600 vibrations per hour, roughly 42 hours of power reserve. It hacks — pull the crown and the second hand stops dead, so you can set it to the second rather than somewhere approximately right. It hand-winds, which many cheap automatics don't. It's the movement family Seiko used in its own watches for years, and it's the reason the entire microbrand industry exists.

In practice you get a watch that keeps reasonable time, never needs a battery, and can be serviced by any competent watchmaker anywhere. It won't match a chronometer-certified Swiss movement for accuracy — expect somewhere in the region of ten to twenty seconds a day. It will run for a decade with no attention at all, which for most people is the more useful quality.

Case, size and how it wears

The case is around 40mm across and 13.3mm thick, in brushed 316L stainless steel with polished bevels running along the case sides. That combination of brushed surfaces broken by a thin polished line is a finishing technique usually reserved for more expensive watches, and it catches light properly on the wrist.

Forty millimetres is the sweet spot for a diver — big enough to read at a glance, small enough to sit under a cuff. Lug width is 20mm, the most common strap size there is, so swapping to leather, rubber or NATO costs a few pounds and takes two minutes.

The bezel is the standout

At this price the bezel is usually where the compromise shows: gritty action, poor alignment, a hollow rattle when you turn it.

Not here. The 120-click unidirectional bezel has tight, evenly resistive action with no back-play — it lands where you put it. The ceramic insert resists the scratching and fading that ruins painted aluminium bezels within a year of real wear. Ceramic at this money was unheard of five years ago, and it's the single component that most clearly signals the watch is better made than its price suggests.

Unidirectional isn't just tradition, incidentally. A dive bezel turns anticlockwise only, so if it's knocked underwater it can only ever show more elapsed time than has actually passed — erring towards surfacing early rather than running out of air.

Lume, and the detail most reviews miss

Seestern uses Super-LumiNova BGW9 on the hands, markers and bezel pip. It charges fast and burns strong and even, rather than the patchy, quickly fading glow common at this end of the market.

The detail worth knowing is the fully lumed date wheel. The date numerals themselves glow. That's genuinely uncommon at any price, let alone this one, and it suggests somebody at Seestern actually cares about the details.

What isn't perfect

No watch at this money is flawless, and pretending otherwise helps nobody.

The NH35A is reliable rather than precise. Ten to twenty seconds a day is normal for the calibre and irrelevant for daily wear, but if you want Swiss-certified accuracy this isn't the watch.

Finishing is good, not flawless. Under a loupe you'll find the odd imperfection. At arm's length, which is where watches are actually seen, it looks considerably more expensive than it is.

Who should buy it

Buy this if you want a genuine mechanical dive watch with real specification, something visually distinct from the sea of Submariner clones, and you'd rather spend the difference elsewhere.

Look elsewhere if you need chronometer accuracy.

For everyone else, this is about as much watch as money buys at this level. The bezel and the lume in particular are better than they have any right to be.

Specifications

Movement: Seiko NH35A automatic, 24 jewels, hacking and hand-winding, ~42-hour reserve
Case: 316L stainless steel, brushed with polished bevels
Crystal: Sapphire
Water Resistance: 200m / 20 ATM
Case Diameter: ~40mm
Case Thickness: ~13.3mm
Lug Width: 20mm
Bezel: 120-click unidirectional, ceramic insert
Band: Jubilee-style stainless steel, folding clasp with safety catch
Dial: Date window, Super-LumiNova BGW9 on hands, markers, bezel pip and date wheel
Features: Automatic self-wind, hacking seconds, date

Frequently asked questions

Is the Seestern SUB600T a good watch?

Yes, particularly at its price. It uses a genuine Seiko NH35A automatic, sapphire crystal, a ceramic bezel and carries a 200m water resistance rating. Its bezel action is notably better than several more expensive alternatives, and the fully lumed date wheel is unusual at any price point.

What is the Seestern SUB600T a homage to?

The DOXA SUB 300T, a 1960s cushion-cased diver. The naming follows directly — DOXA's SUB 300T, Seestern's SUB 600T — and the case shape and bold colourways follow DOXA rather than Rolex.

Can you actually dive with a Seestern SUB600T?

Its 200m (20 ATM) rating covers recreational scuba diving, as well as swimming, snorkelling and surface water sports. As with any dive watch, seals should be checked periodically if you dive regularly.

Is Seestern a good watch brand?

Seestern has built a solid reputation among affordable-watch enthusiasts for specification and value, particularly for bezel quality and lume. It's a microbrand rather than a heritage house, and priced accordingly.

How accurate is the Seiko NH35?

Typically within ten to twenty seconds a day out of the box. That's normal for the calibre and can often be improved by regulation. It's reliable rather than chronometer-grade.

What strap size does the Seestern SUB600T take?

20mm, which is the most widely available strap width — so aftermarket leather, rubber, NATO and metal options are plentiful and inexpensive.

Related reading

The NH35 inside the SUB600T is covered in full detail in our NH35 vs Miyota 8215: Which Automatic Watch Movement Should You Buy?, including how it compares to the Miyota 8215 used elsewhere in our range. And if you're weighing it against its Seestern sibling, our Seestern SUB300T vs SUB600T comparison sets the two side by side.