Orient Kamasu vs. Seiko 5 Sports: Which Is the Better Buy Under $500?

	OrientKamasu	Seiko5 Sports SKX Series
Price (US)	$375 (edge)	$450
Reference	RA-AA0003R39B	SRPL83
Movement	Orient F6922, automatic	Seiko 4R36, automatic
Power reserve	About 40 hours	About 41 hours
Rated accuracy	+25/−15 sec/day (edge)	+45/−35 sec/day
Hacking / hand-winding	Yes / Yes	Yes / Yes
Jewels	22	24
Beat rate	21,600 vph	21,600 vph
Case diameter	41.8mm	42.5mm
Thickness	12.8mm (edge)	13.9mm
Lug to lug	47mm	46mm
Lug width	22mm	22mm
Crystal	Sapphire (edge)	Curved Hardlex
Caseback	Not published	Exhibition, screw-down (edge)
Water resistance	200m (edge)	100m
Bezel	Unidirectional, 120 clicks, stainless steel bezel	Unidirectional, glass insert
Crown	Screw-down (edge)	Push/pull
Lume	Luminova	LumiBrite
Bracelet / strap	Steel bracelet, fold-over clasp with safety	Steel bracelet, three-fold clasp
Warranty	3 years (Orient Watch USA)	3 years (Seiko USA)

Price

The Kamasu, reference RA-AA0003R39B, is $375 at Orient Watch USA.

Seiko USA lists the 5 Sports SKX Series SRPL83, the blue-dial version on a steel bracelet, at $450. On price alone, the Orient is $75 cheaper than the Seiko it is most often cross-shopped against.

Seiko also has a cheaper way into the range. The older SRPD51 and SRPD55 are still listed at $350, which is $25 less than the Kamasu. They use the same 4R36 caliber, the same 42.5mm diameter and the same 100m rating as the SRPL83, with a Hardlex crystal and a 13.4mm case. The glossy glass bezel insert belongs to the newer SKX Series.

So the SRPD saves $25 against the Kamasu, while giving up the same things the SRPL83 gives up.

Which references

The table above uses the red Kamasu and the blue SRPL83, but both watches come in other versions. Orient sells the Kamasu in black and blue at the same price, and the SRPD comes in blue or black. Prices and stock were checked on the makers’ US sites on October 6, 2026.

Design

The Seiko’s appeal starts with its outline. When Seiko revamped the 5 Sports range in 2019, the new models were plainly inspired by the SKX007, and Monochrome describes the SKX Series case as directly modeled on it. The SKX was an ISO-certified diver with a screw-down crown, and Monochrome calls it “a genuine icon of affordable watchmaking”. The 5 Sports keeps the silhouette but not the certification or the screw-down crown. Its push/pull crown sits at 4 o’clock.

The SRPL83’s distinguishing detail is a glossy glass bezel insert with the 60-minute scale printed on its underside, which Monochrome credits with adding depth and a play of light. It sits on a unidirectional bezel, and the case mixes brushed and polished surfaces.

The Kamasu, on the market since around 2019, has no comparable back story and does not pretend to. Its case is brushed on top with polished sides, and its unidirectional bezel turns in 120 clicks. Orient does not say what the insert is made of. The overall look is more contemporary than the Seiko’s and leans harder on color, at least in the wine red reference covered here.

On design heritage, the Seiko holds the stronger card. The Orient has to win on other grounds.

Movement

Both watches use their makers’ own automatic calibers, and on paper they are close to twins. Orient’s F6922 has 22 jewels, beats at 21,600 vph, stores about 40 hours, hacks, hand-winds and shows the day and date. It debuted in 2016 and, like Orient’s other movements, is made in Akita Prefecture by Akita Epson.

Seiko’s 4R36 has 24 jewels, the same 21,600 vph and about 41 hours of reserve, with hacking, hand-winding and a day-date. The jewel counts and the one-hour reserve gap do not separate them in any useful way.

Two things do. The first is the accuracy rating, covered below, where Orient sets a tighter tolerance. The second is visibility. The Seiko has a see-through screwed caseback, so the 4R36 is on show. Orient does not state the Kamasu’s caseback type, and secondary sources describe it as solid, so the F6922 is most likely out of sight.

For more on how Orient’s calibers are made, see our guide to Orient’s in-house mechanical movements.

Case and Dimensions

The Kamasu measures 41.8mm across, 12.8mm thick and 47mm lug to lug, with 22mm lugs and a screw-down crown. The Seiko SRPL83 measures 42.5mm, 13.9mm and 46mm, also with 22mm lugs, and a push/pull crown at 4.

So the Orient is 0.7mm narrower and 1.1mm thinner, while the Seiko is 1mm shorter from lug tip to lug tip. Both cases are steel, and the shared 22mm lug width means straps move freely between them.

The cheaper SRPD trims the Seiko’s thickness to 13.4mm by Seiko’s figure, which narrows the gap to the Kamasu without closing it.

Dial

The Kamasu dial is deep wine red. Reviewers describe the finish as sunburst, while Orient’s page simply calls it red. Applied indices with silver surrounds mark the hours, with dots at most positions, rectangles at 6 and 9 and a trapezoid at 12. The hour hand is an arrowhead and the minute hand a lance. The day and date sit at 3, and the hands and markers use Luminova.

The SRPL83 has a blue dial with applied rectangular markers and LumiBrite, Seiko’s own luminous material. It also shows the day and date.

Both are conventional, legible dive layouts. The Orient’s mix of index shapes aids orientation, and the Seiko’s plain rectangles are closer in spirit to the SKX. Neither has a clear edge.

Crystal

This is the clearest win in the comparison. The Kamasu has a sapphire crystal. The Seiko has curved Hardlex, Seiko’s hardened mineral glass, and the SRPD has flat Hardlex.

Sapphire is considerably harder than mineral glass and far better at resisting the fine scratches that build up on a watch worn every day. Under $400, sapphire is still not a given, and it is the most practical advantage the Orient holds.

The Seiko does use glass in one other place. Its bezel insert is glass, while Orient does not name the material of the Kamasu’s insert. That is a genuine point in the Seiko’s favor, though it is the crystal that protects the dial.

Accuracy

Orient rates the F6922 at +25/−15 seconds a day. Seiko rates the 4R36 at +45/−35. Orient’s tolerance window is 40 seconds wide, and Seiko’s is 80.

A rating is the range a maker will stand behind, and it says nothing certain about how an individual watch will run. But the published specification is the only fair basis for comparison, and on that basis the Orient is clearly ahead. Our guide to reading a watch spec sheet explains how to weigh figures like these.

Water Resistance

The Kamasu is rated to 200m and has a screw-down crown. Orient makes no ISO claim, and the dial reads “water resistant” rather than carrying a diver’s designation.

The Seiko is rated to 100m, with a push/pull crown and a screwed caseback. It is not certified to ISO 6425, the international standard for divers’ watches, and it is not a rated diver. It has a diver’s bezel and a diver’s look, but it is a sports watch.

Neither watch is a certified diver, then, but the Kamasu has twice the rating and the more secure crown. The SKX that inspired the Seiko did carry ISO certification, which is one of the things the 5 Sports does without. Buyers who need certification from Orient have to look further up the range, to the Orient Star Sports Diver RE-AU0301B00B. It is ISO 6425 rated and listed at $700, but it was out of stock at Orient Watch USA at the time of writing.

On the Wrist

On the published dimensions, these two are closer than their diameters suggest. The Seiko is wider and thicker, but its 46mm lug-to-lug is the shortest figure in this comparison, and lug-to-lug length often decides whether a watch overhangs a smaller wrist.

The Kamasu’s advantage is height. At 12.8mm it sits 1.1mm lower than the SRPL83, which matters more under a shirt cuff than a diameter difference of under a millimeter. Its 47mm lug-to-lug is still compact for a 41.8mm diver.

The Seiko’s crown placement is the other factor. A crown at 4 o’clock is tucked toward the lower edge of the case and is less likely to press into the back of the hand. On paper, the Orient is the slimmer watch and the Seiko the slightly shorter one, and neither looks oversized by current standards.

Quality

Neither maker publishes much about finishing, so this section leans on materials and on what reviewers have reported.

The Kamasu’s bracelet is an oyster-style design in 316L steel, with split pins and a stamped fold-over clasp with a safety catch. Reviewers report that its end links are hollow, though Orient does not confirm it. A stamped clasp and hollow links are the usual places where a watch at this price saves money, and they are where the $375 shows.

The Seiko comes on a steel bracelet with a three-fold clasp. Its case combines brushed and polished surfaces, and the glass bezel insert and display back give it a more finished presentation than its crystal and crown would suggest.

The Orient’s case for quality rests on its components, a sapphire crystal and a screw-down crown. The Seiko’s rests on its details. Both are reasonable ways to spend a budget, and the Orient’s choices are the ones that protect the watch.

Long-Term Ownership

Both come with three years of cover. Orient Watch USA offers a 3-year warranty, and Seiko USA offers 3 years on purchases made from July 1, 2024.

Over years of wear, the sapphire crystal should keep the Kamasu’s dial clear of the scratches that tend to collect on mineral glass. The Seiko’s glass bezel insert should resist scuffs well, although glass is a brittle material. A push/pull crown is quicker to use. A screw-down crown has to be screwed back in after every adjustment, and in return it gives better protection against water.

The 4R36 has one practical advantage. Seiko’s 4R calibers power much of the value end of the market, so it is likely to be familiar to almost any independent watchmaker.

Value

By the numbers, the Kamasu gives more for less. For $375 it brings a sapphire crystal, a screw-down crown, 200m of water resistance, a tighter accuracy rating and a thinner case. The SRPL83 asks $75 more and returns a glass bezel insert, a display back and the SKX outline.

The Seiko sells a famous outline. The Orient sells more of the hardware a dive watch actually needs.

The SRPD changes the arithmetic a little. At $350 it is the cheapest watch here, and for someone who mainly wants the SKX shape on a budget it is a sensible buy. It just should not be bought as a diver. Orient has a cheaper diver of its own, the AA02 at $290, with the same F6922 and a 200m rating but a mineral crystal.

If the Kamasu looks like the right fit, our full Kamasu review goes further, and our list of the best automatic watches under $500 puts both watches in a wider field. For a Swiss alternative at a much higher price, see the Kamasu against the Hamilton Khaki Navy Scuba.

Verdict

Best Value

Orient Kamasu

Best Movement

Orient Kamasu

Best Finishing

Seiko 5 Sports SKX Series

Editor’s Pick

Orient Kamasu

For most buyers who want a dive watch at this price, the Kamasu is the one to buy. It costs $75 less than the SRPL83 and brings a sapphire crystal, a screw-down crown, twice the water resistance and a tighter accuracy rating, which are the specifications that count on a watch meant to be worn hard. Its Best Movement award rests on that rating alone, since the two calibers are otherwise near twins.

The Seiko takes Best Finishing for the details that lift its presentation, the glass bezel insert and the display back, and it is the right choice for anyone who wants the SKX shape or likes to watch the balance swing. If budget decides it, the SRPD at $350 is the cheapest way in. Buy either Seiko knowing it is a 100m sports watch, not a diver.