Head-to-Head Comparison

Updated September 5, 2026

Seiko 5 Sports 5KX vs Seiko Prospex 62MAS Modern Re-interpretation

Seiko's timepiece meets Seiko's diver

Quick Verdict

The Seiko 5 Sports 5KX ($250–$500) offers Seiko In-House Automatic precision in the tier below the Seiko Prospex 62MAS Modern Re-interpretation ($1,000–$1,500). The 5 Sports 5KX measures 42.5mm and is rated 100m (10 ATM). The Prospex 62MAS Modern Re-interpretation counters with Made in Japan craftsmanship and 200m (20 ATM) water resistance. Both are exceptional watches for their respective tiers.

Seiko5 Sports 5KX$250–$500 Check price SeikoProspex 62MAS Modern Re-interpretation$1,000–$1,500 Check price

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Seiko

5 Sports 5KX

$250–$500

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Seiko

Prospex 62MAS Modern Re-interpretation

$1,000–$1,500

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Specifications Compared

Feature	Seiko 5 Sports 5KX	Seiko Prospex 62MAS Modern Re-interpretation
Price	$250–$500	$1,000–$1,500
Case Size	42.5mm	40.5mm
Movement	Automatic Caliber 4R36	Automatic 6R35
Caliber Type	Seiko In-House Automatic	Seiko In-House Automatic
Power Reserve	41 Hours	70 Hours
Water Resistance	100m (10 ATM)	200m (20 ATM)
Crystal	Hardlex Crystal	Sapphire
Case Material	Stainless Steel	Stainless Steel with Super-Hard Coating
Origin	Made in Japan	Made in Japan

Category-by-Category Analysis

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Design & Aesthetics

Edge: Draw

Seiko's design language vs Seiko's approach

The Seiko 5 Sports 5KX features a Stainless Steel case at 42.5mm with Hardlex Crystal protection. The Seiko Prospex 62MAS Modern Re-interpretation offers Stainless Steel with Super-Hard Coating construction at 40.5mm with Sapphire. Both represent their brand's distinct design philosophy and heritage.

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Movement & Performance

Edge: Seiko

Automatic Caliber 4R36 vs Automatic 6R35

The 5 Sports 5KX runs the Automatic Caliber 4R36 (Seiko In-House Automatic, 41 Hours power reserve) at 21,600 vph (3 Hz) frequency. The Prospex 62MAS Modern Re-interpretation uses the Automatic 6R35 (Seiko In-House Automatic, 70 Hours reserve) at 21,600 vph (3 Hz). The Prospex 62MAS Modern Re-interpretation offers a longer power reserve.

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Wearability & Fit

Edge: Seiko

42.5mm vs 40.5mm — different wrist presence

At 42.5mm, the 5 Sports 5KX has a bolder wrist presence compared to the Prospex 62MAS Modern Re-interpretation at 40.5mm. Water resistance differs: 100m (10 ATM) vs 200m (20 ATM).

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Value & Cost of Ownership

Edge: Seiko

Seiko sits in the lower tier

The Seiko 5 Sports 5KX sits at $250–$500 and the Seiko Prospex 62MAS Modern Re-interpretation at $1,000–$1,500. On the specs that outlast any price: the 5 Sports 5KX uses Hardlex Crystal with 41 Hours, against Sapphire and 70 Hours on the Prospex 62MAS Modern Re-interpretation. Service intervals are typically 5-7 years for both.

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Water Resistance

Edge: Seiko

100m (10 ATM) vs 200m (20 ATM)

The 5 Sports 5KX is rated to 100m (10 ATM) while the Prospex 62MAS Modern Re-interpretation handles 200m (20 ATM). The Prospex 62MAS Modern Re-interpretation offers superior water resistance.

Our Verdict

Seiko

5 Sports 5KX

Choose the Seiko 5 Sports 5KX if you prioritize Seiko In-House Automatic engineering, Made in Japan craftsmanship, and 100m (10 ATM) water resistance. At $250–$500, it delivers Automatic Caliber 4R36 with 41 Hours power reserve.

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Seiko

Prospex 62MAS Modern Re-interpretation

Choose the Seiko Prospex 62MAS Modern Re-interpretation if you value Seiko In-House Automatic technology, Made in Japan heritage, and 40.5mm proportions. At $1,000–$1,500, the Automatic 6R35 with 70 Hours power reserve makes it a compelling choice.

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The Bottom Line

The Seiko 5 Sports 5KX and Seiko Prospex 62MAS Modern Re-interpretation represent two distinct approaches to fine watchmaking — the Seiko bringing Made in Japan tradition while Seiko delivers Made in Japan engineering.

Frequently Asked Questions

For water, the Seiko Prospex 62MAS Modern Re-interpretation is rated 200 m against 100 m, which is the difference between swimming and diving on one side and splashes on the other. On price, the Seiko 5 Sports 5KX sits a band lower ($250–$500 against $1,000–$1,500), so it is the cheaper way into the category. Neither is better at everything; the spec table above shows movement, case size, water resistance and crystal side by side so you can weigh what matters to you. We do not test units, so this is the makers' data, not a bench result.

The Seiko 5 Sports 5KX offers better upfront value, sitting a tier lower at $250–$500. However, the Seiko Prospex 62MAS Modern Re-interpretation may justify its premium with superior finishing, heritage, or resale value.

Both are suitable for daily wear. The 5 Sports 5KX at 42.5mm with 100m (10 ATM) water resistance handles everyday situations. The Prospex 62MAS Modern Re-interpretation at 40.5mm with 200m (20 ATM) is similarly capable. The 5 Sports 5KX uses Hardlex Crystal while the Prospex 62MAS Modern Re-interpretation uses Sapphire.

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How This Page Was Made

Our comparisons are generated from a hand-maintained specification database and reviewed under our editorial standards. We use AI tools to assemble pages from that data. We don’t invent specs: every number traces back to the database, and when we correct an entry, the fix is applied site-wide. As an Amazon Associate, The Horologist earns from qualifying purchases.