Name: Seiko 5 Sports SKX Style SBSA001 SBSA001
Brand: Seiko
SKU: SBSA001

The SBSA001 is the Japanese-market answer to the SKX's discontinuation: a 42.5mm automatic diver that picks up where that cult classic left off, without pretending to be something it isn't. You get a legitimate tool watch at an honest price, built around a movement Seiko has refined for decades.

What it is

Seiko killed the SKX007 in 2019 after more than two decades in production, leaving a gap in the affordable automatic diver segment that the brand immediately moved to fill with a relaunched 5 Sports lineup. The SBSA001 is the domestic Japanese version of that relaunch, sold through Seiko's home-market channels while the SRPD series covered international distribution. Both share the same SKX-inspired case proportions and crown-at-4 layout, but the SBSA001 carries Japanese-market finishing standards and packaging.

The day-date complication via the 4R36 caliber gives it slightly more daily utility than a pure three-hand diver. It arrived at a moment when used SKX prices were already climbing on nostalgia demand, and the 5 Sports line became the rational alternative for buyers who wanted the spirit of the SKX at a current-production price.

Buying notes

The 4R36 hacks but does not hand-wind, which is a genuine inconvenience when setting time precisely. At 42.5mm with the crown at 4, the case wears larger than its diameter suggests, and buyers with smaller wrists should try it before committing. The bezel insert on early production SBSA001 units can show uneven lume application; inspect under a light before purchase.

The crystal is Hardlex, not sapphire, so scratching is a matter of when, not if. Gray-market units sold as SBSA001 are sometimes actually SRPD variants with the dial legend altered, so confirm the reference number on the caseback matches the paperwork.

Market read

New SBSA001 units have typically traded in the 250 to 350 USD range depending on condition and seller. Used examples in good shape hold value reasonably well because demand for the 5 Sports line remains steady. The Japanese-market designation does not command a meaningful premium over SRPD variants in practice, though some collectors pay a small difference for the original packaging and domestic documentation.

Service expectations

The 4R36 is a workhorse caliber with widely available parts and well-documented service procedures. A full service including timing adjustment typically runs 150 to 250 USD at an independent watchmaker familiar with Seiko movements. Seiko's official service network will also handle it, generally at higher cost but with OEM parts guaranteed.

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Movement tier: unclassified · caliber Seiko Cal. 4R36: in-house automatic, 21,600bph, 41h PR, 24j; hackable, manually windable; used in Seiko 5 Sports and entry Prospex models · 41h power reserve

Also uses Seiko Cal. 4R36

Large case: suits wrists 7 in+ (18 cm+)

42.5 mm case. A bold, statement-size wear. Best suited to larger wrists where the case sits flush.

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Authentication

Primarily a grey-market and wrong-reference concern; the correct movement is 4R36, not the older 7S26.

Known issues in the market

Examples sold as SBSA001 that actually contain Cal. 7S26 (non-hackable, no hand-winding), often from older SKX parts.
Reference numbers on caseback that do not match SBSA001 (common with grey-market rebranding).
Bezel inserts with fewer than 120 clicks or with bidirectional rotation (this bezel is unidirectional).
Day display showing only English (should show English plus one additional language for this reference).

Area	What to check	What is correct	Red flag
caseback	Reference number SBSA001 engraved on caseback	Caseback exterior shows "SBSA001" and "4R36" (or related markings); "DIVERS 200m" rating engraved; serial number on case side matches Seiko format	Reference number is SKX007, SKX009, or any 7S26-era code; reference absent entirely; poorly engraved or re-engraved reference
movement	Cal. 4R36 vs Cal. 7S26	Cal. 4R36 hacks (seconds hand stops when crown is pulled to time-set position); can be hand-wound; 21,600bph (6 beats per second)	Movement that does not hack (seconds hand continues when crown pulled); Cal. 7S26 identification marks on rotor
dial	Day/date display with dual language	Day display at 12 shows English abbreviation (MON, TUE, etc.) and one other language; date window at 3; dial text is crisp	Day display in English only; date window missing; blurred day or date numerals
case	Unidirectional bezel with 120 clicks	Bezel rotates counterclockwise only; 120 positive clicks per full rotation; insert has minute markings from 0 to 60 with triangle at 12	Bezel that rotates in both directions; fewer than 120 clicks; soft or inconsistent detents
case	41.3mm case proportions	Case is approximately 41.3mm; lug width 22mm; cushion-influenced case shape carrying SKX heritage; mixed brushed and polished surfaces	Case diameter significantly different from 41.3mm; fully polished case (should be mixed); aftermarket case without Seiko caseback markings

Common legitimate replacements

Bracelets are frequently replaced with NATO or rubber on used examples.
Bezel inserts are available as genuine Seiko parts and are a common legitimate replacement.

Expert resources: Seiko serial dating and reference verification at seikousa.com. WatchUSeek Seiko Sport forum covers SBSA001. The 4R36 vs 7S26 distinction is the key authentication check.

Authentication guide

Last reviewed June 2026

The SBSA001 is the 5 Sports that replaced the SKX line, carrying the same SKX-adjacent silhouette with the upgraded 4R36 movement and a mineral crystal. At this price point, the primary risk is not sophisticated reproductions but rather worn or damaged examples misrepresented as new. The mineral crystal is intentionally correct; do not confuse it for evidence of an incorrect part.

Known reproduction risks

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Reproductions of the SBSA001 are uncommon given the watch's retail price makes buying new more practical for most buyers. The main market risk is misrepresented condition.

Crown at 3 o'clock without the asymmetric case guard
Caseback with an SKX reference number (older, unrelated model)
Sapphire crystal presented as original

Dial variants by era

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Era	Description	Identifiers
2019 to present	Black dial with mixed Arabic numerals and applied indices, day and date display at 3. The SBSA001 has a distinctly squared-off case with an asymmetric crown-guard protection, referencing the SKX design language.	Black dial with applied rectangular indices and bold Arabic numerals at 12, 6, and 9 Day and date window at 3 "5 SPORTS" and "AUTOMATIC" printed on the dial Unidirectional aluminum bezel Asymmetric crown guard integrated into the case at 4 o'clock Mineral crystal (not sapphire -- this is correct for this reference)

Service part flags

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Crystal

Original: Mineral crystal, not sapphire. The mineral crystal is original and intentional for this reference. A sapphire crystal replacement is an aftermarket modification, not an upgrade.

Replacement tells

Sapphire crystal presented as an "upgrade" -- this is non-original
Crystal with incorrect dome profile relative to the case bezel

Dial

Original: Black matte dial with applied indices and printed text. The day wheel shows the full day name in two languages on JDM examples.

Replacement tells

Day wheel showing only one language when the example is claimed to be JDM
Applied indices sitting at uneven heights
Dial with glossy surface instead of matte

Bezel

Original: Unidirectional aluminum insert, 120-click action. The pip at 12 is a lumed triangle.

Replacement tells

Bezel that rotates bidirectionally
Pip at 12 without lume fill
Ceramic insert instead of aluminum

Crown

Original: Push-pull crown at 4 o'clock with the asymmetric guard. The crown is not screw-down.

Replacement tells

Crown repositioned to 3 o'clock without the guard
Screw-down crown, incorrect for this reference

Case back markings

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2019 to present

SBSA001 reference number
"100M" water resistance designation
Seiko S logo on the caseback
Cal. 4R36 designation
Serial number in standard Seiko format

Movement tells

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Cal. 4R36 runs at 21,600 bph (6 ticks per second). Any SBSA001 with a faster tick rate has a movement swap.
The 4R36 has day and date display, hackable seconds, and manual winding. Verify all three at purchase.
Power reserve is approximately 41 hours. A fully wound example that runs fewer than 35 hours is due for service.
The 4R36 movement is less refined than the 6R35 found in higher Prospex and Presage models; minor beat rate variation is normal. A movement that runs more than 30 seconds per day fast or slow needs adjustment.

Sources: Seiko 5 Sports SBSA001 product page.