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Dial&Lug
The bezel of a steel dive watch photographed close up

Kamasu vs Turtle

Orient Kamasu vs Seiko Turtle

The two affordable divers everyone shortlists. One has the better glass; the other has the better paperwork. Both are right answers.

By Sawyer V. · Published

The short answer

The Kamasu has the better specification sheet — sapphire against Hardlex, and a 41.8mm case with a published 46.8mm lug-to-lug. The Turtle has the better future — an ISO diver's marking and a published $176 overhaul on the most widely serviced caliber in the US. Buy the Kamasu to stay unscratched; the Turtle to cost less to keep.

If you have spent any time choosing an affordable dive watch, you have ended up here. These two appear together in almost every shortlist because each is the best answer to a slightly different question, and neither is a bad choice. The job of this page is to make the difference exact.

Side by side

Orient KamasuSeiko Prospex Turtle SRPE93
Case41.8mm45mm cushion
Lug-to-lug46.8mmNot published — no protruding lugs
Thickness12.8mm13.4mm
CrystalSapphireHardlex
Water resistance200m200m, ISO diver's marking
CrownScrew-downScrew-down
MovementOrient F6922, in-house, hacking, hand-windingSeiko 4R36, hand-winding
Warranty3 years3 years
Published overhaul priceNone for the US$176
Lug width22mm22mm

On prices: we publish no figure we have not verified today, so every buy button reads "Check price on Amazon". Service prices on this page are the manufacturers' own published figures.

How we picked

We have not worn these watches. What follows is what we checked instead, on documents you can open yourself — the same criteria, in the same order, on every roundup on this site. The full method is on the methodology page.

  1. 01Crystal

    The clearest difference. Sapphire on the Kamasu, Hardlex on the Turtle — and neither can be polished back.

  2. 02Certification

    Seiko prints the ISO 6425 "diver's" marking on the Turtle. Orient rates the Kamasu 200m without claiming the diver's standard.

  3. 03Cost to keep

    Seiko publishes $176 to overhaul the 4R36. Orient publishes no US service prices.

  4. 04Fit

    The Kamasu is a conventional 41.8mm case; the Turtle's 45mm cushion case has no protruding lugs and wears smaller than it reads.

  5. 05Movement

    Orient's in-house F6922 hacks and hand-winds. Seiko's 4R36 hand-winds and is the most commonly serviced caliber in the country.

Disclosure · Some links below are Amazon affiliate links. If you buy through one we earn a commission at no extra cost to you. It does not decide what goes on this page or in what order — here is exactly how that works.

Quick picks

Ranked on the Keep Score below — six published specifications, weighted identically on every page. The last row is the one we would not buy.

#WatchBest forKeep ScorePrice
1

Orient Kamasu RA-AA0004E39B

Sapphire, 200m, a screw-down crown and a 120-click unidirectional bezel.

Looking new in ten years9.0/10
Check price
2

Seiko Prospex Turtle SRPE93

ISO diver's marking and the cheapest published mechanical overhaul there is.

The lowest twenty-year cost, and a certified diver8.4/10
Check price
—

Seiko 5 Sports SRPD55

The third watch in every Kamasu-or-Turtle thread — rated 100m, not a diver.

Skip this one

Not this comparison8.0/10
Check price

Keep Score is arithmetic, not opinion — six published specifications, weighted the same way on every page. The formula is on our methodology page, so you can re-run it yourself.

01

Orient Kamasu RA-AA0004E39B

Best for: Looking new in ten years

9.0/10

Keep Score

Crystal
2.5/2.5
Serviceability
2.5/2.5
Water resistance
1.5/1.5
Warranty
1.05/1.5
Strap standard
1/1
Cost-to-keep transparency
0.4/1
Check price on Amazon

#ad Affiliate link · We publish no price we have not verified today

The crystal decides this for most people. On a diver — the style most likely to meet a doorframe — sapphire is the difference between a face that looks new in ten years and one that shows every knock. Seiko does not fit sapphire at this level; Orient does.

You also get a movement that hacks, which Orient states on the product page, and a conventional case at 46.8mm lug-to-lug that fits most wrists predictably. What you give up is a published service price.

On paper this is the best value in the category and it is not close: sapphire and a hacking, hand-windable in-house caliber at a price where Seiko still fits Hardlex. Orient's three-year warranty is longer than Hamilton's or Tissot's.

Manufacturer specifications for the Orient Kamasu RA-AA0004E39B
MovementOrient F6922 in-house automatic, hand-winding, hacking
Power reserve40 hours
Case41.8mm stainless steel
Lug-to-lug46.8mm
Thickness12.8mm
Lug width22mm
Crystalsapphire
Water resistance200m
Warranty3 years

Specifications read from Orient Watch USA product page, RA-AA0004E39B.

02

Seiko Prospex Turtle SRPE93

Best for: The lowest twenty-year cost, and a certified diver

8.4/10

Keep Score

Crystal
1.3/2.5
Serviceability
2.5/2.5
Water resistance
1.5/1.5
Warranty
1.05/1.5
Strap standard
1/1
Cost-to-keep transparency
1/1
Check price on Amazon

#ad Affiliate link · We publish no price we have not verified today

Seiko may only print "diver's" on the dial if the watch meets ISO 6425, a harder regime than the general water-resistance standard — so the Turtle is certified in a way the Kamasu does not claim to be.

The 4R36 overhaul is a published $176, which at Seiko's recommended three-year interval makes this the most predictable mechanical diver there is to own. The cushion case reads 45mm and wears smaller; the Hardlex is the cost.

Seiko rates this at 200m as a diver's watch, not merely water-resistant — screw-down crown, screw case back, unidirectional bezel. The 45mm figure is misleading: the cushion case has no protruding lugs.

Manufacturer specifications for the Seiko Prospex Turtle SRPE93
MovementSeiko 4R36, automatic with manual winding, 24 jewels
Power reserve41 hours
Case45mm stainless steel
Lug-to-lugNot published
Thickness13.4mm
Lug width22mm
Crystalhardlex
Water resistance200m
Warranty3 years

Specifications read from Seiko Watch Corporation product page, SRPE93.

Skip this one

Seiko 5 Sports SRPD55

Best for: Not this comparison

8.0/10

Keep Score

Crystal
1.3/2.5
Serviceability
2.5/2.5
Water resistance
1.1/1.5
Warranty
1.05/1.5
Strap standard
1/1
Cost-to-keep transparency
1/1
Check price on Amazon

#ad Affiliate link · We publish no price we have not verified today

The Seiko 5 Sports SRPD55 appears alongside these two constantly, because it has a rotating bezel, dive-watch styling and the same 4R36 as the Turtle at a lower level.

Seiko rates it 100m and does not print "diver's" on the dial. For swimming that is fine; as a replacement for either watch above, it is not the same object.

If the budget is what pushed you toward it, the Turtle is the same movement and service path with a genuine 200m diver's rating — the [dive watches under $500](/styles/dive-watches/best-under-500) page ranks the whole tier.

The 4R36 is the most commonly serviced mechanical caliber in the United States and Seiko publishes a flat $176 price to overhaul it. That single fact does more for a twenty-year horizon than any spec on the case.

Manufacturer specifications for the Seiko 5 Sports SRPD55
MovementSeiko 4R36, automatic with manual winding, 24 jewels
Power reserve41 hours
Case42.5mm stainless steel
Lug-to-lug46mm
Thickness13.4mm
Lug width22mm
Crystalhardlex
Water resistance100m
Warranty3 years

Specifications read from Seiko Watch Corporation product page, SRPD55.

Which one to buy

  • Buy the Kamasu if you want the watch to look new for as long as possible, you like a conventional case shape, or you want a hacking movement for setting to the second.
  • Buy the Turtle if you want a certified diver, the lowest predictable running cost of any mechanical dive watch, or a case that wears smaller than its diameter on a flat wrist.
  • Buy either if you want 200m, a screw-down crown, a three-year warranty and a caliber made in enough volume that parts will exist in twenty years. They share all of that.

The Hardlex fix

The Turtle's weakness is the one most easily undone: a sapphire replacement crystal fitted at the first overhaul is a routine job on a watch this common, and it turns the Turtle into a watch that beats the Kamasu on every axis except purchase price. The Kamasu's weakness — no published service price — cannot be fixed by anyone but Orient.

For the broader argument between the two brands, see Seiko vs Orient.

Questions people actually ask

Is the Orient Kamasu better than the Seiko Turtle?

On the specification sheet, yes — sapphire against Hardlex, and a hacking movement. On ownership, no — the Turtle carries the ISO diver's marking and a published $176 overhaul price, and Orient publishes no US service prices.

Which is bigger, the Kamasu or the Turtle?

The Turtle reads larger at 45mm against 41.8mm, but its cushion case has no protruding lugs and wears smaller than the number suggests. The Kamasu's published lug-to-lug is 46.8mm; Seiko does not publish one for the Turtle.

Is the Kamasu a real dive watch?

It is rated 200m with a screw-down crown and a unidirectional bezel, which covers everything a diver structurally needs. Orient does not claim the ISO 6425 diver's standard for it; Seiko does for the Turtle.

Can you put a sapphire crystal in a Seiko Turtle?

Yes — a replacement sapphire crystal fitted at service is a routine job on a watch this common, and it removes the Turtle's main disadvantage against the Kamasu.

Sources

Every specification and figure on this page came from one of these documents. Where a manufacturer does not publish something, the page says so rather than filling the gap.

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