Seiko Prospex vs Seiko Prospex

Side-by-side comparison of specifications and features

SeikoProspex

SPB143

SeikoProspex

SPB155 (Baby Alpinist)

Key Differences

Best Value

Seiko Prospex (Ref. SPB155 (Baby Alpinist))

Starting from $500

Biggest Price Drop

Seiko Prospex (Ref. SPB155 (Baby Alpinist))

-6.0% in 30 days

Price Comparison

Seiko Prospex

MSRP

$1,200

New

$1,309

Used

$940

Seiko Prospex

MSRP

$725

New

$500

Used

$300

MSRP New (Amazon) Used (eBay)

Comparison of Seiko Prospex, Seiko Prospex
Specification	Seiko Prospex	Seiko Prospex
Pricing
MSRP	$1,200	$725
New Price	$1,309	$500
Used Price (Low)	$940	$300
Used Price (High)	$1,890	$3,000
30-Day Trend	↑ +1.0%	↓ -6.0%
Used Price Range	$940 - $1,890	$300 - $3,000
Identity
Reference	SPB143	SPB155 (Baby Alpinist)
Nickname	N/A	N/A
Style	Diver, Tool	Field, Sports, Tool
Release Era	2020s	2010s
Dimensions
Diameter	40.5mm	38mm
Thickness	N/A	N/A
Lug Width	N/A	N/A
Lug to Lug	N/A	N/A
Movement
Movement	Automatic	Automatic
Power Reserve / Battery	N/A	N/A
Accuracy	N/A	N/A
Case
Case Material	Stainless Steel	Stainless Steel
Crystal	Sapphire Crystal	Sapphire Crystal
Water Resistance	200m (diving)	200m (diving)
Bezel	Unidirectional rotating	Fixed
Dial
Dial Color	Gray	Green
Luminous	Yes	Yes
Community
Review Rating	N/A	N/A
In Collections	N/A	N/A
On Wishlists	N/A	N/A
Forum Threads	N/A	N/A

Quick Summary

Seiko Prospex and Seiko Prospex can look close on a spec sheet, yet the tradeoffs that matter most are usually wrist presence versus easier fit, diver character versus field versatility, entry price versus premium finishing or specs. Treat it as a value-versus-upgrade decision — confirm the extra spend solves a problem you will notice every week.

How to choose

The biggest practical difference is usually movement and upkeep. Start with wrist fit and movement preference, then use water resistance and price to break the tie.

Seiko Prospex

Seiko Prospex is a better fit for buyers who want more wrist presence, mechanical-watch enthusiasts, diver styling.

Seiko Prospex

Seiko Prospex is a better fit for smaller wrists, mechanical-watch enthusiasts, field styling.

Key Differences

Movement and upkeep

Seiko Prospex: automatic movement

Both use the same movement type, so maintenance differences are limited and fit or feature details should decide the purchase.

Size and wearability

Seiko Prospex: 40.5mm

Seiko Prospex: 38mm

Fit is a real separator here — compare case width and lug-to-lug before deciding, especially if wrist comfort matters more than headline features.

Water resistance

Seiko Prospex: 200m

Water resistance is similar on paper, so focus on fit, features, and price instead.

Price and value

Seiko Prospex: $998

Seiko Prospex: $500

There is a real price gap here — treat the more expensive option as an upgrade decision and confirm whether the extra spend buys something you will notice in weekly use.

Style and use case

Seiko Prospex: diver

Seiko Prospex: field

Seiko Prospex leans more diver, while Seiko Prospex pulls toward field use case — pick the one that matches how you will actually wear it.

Crystal and materials

Seiko Prospex: sapphire crystal · steel

Materials are broadly similar, so finish, fit, and price will matter more than the materials list alone.

Choose Seiko Prospex If...

You prefer more dial presence and a larger case feel.
You are specifically shopping for a diver style watch.
You are comfortable paying more for a stronger feature set.

Choose Seiko Prospex If...

You want a smaller case footprint on the wrist.
You are specifically shopping for a field style watch.
You want the lower current entry price.

Price and Value Notes

Seiko Prospex is often the value play at current pricing, while Seiko Prospex makes more sense if you will use its extra features regularly.

There is a real price gap here — treat the more expensive option as an upgrade decision and confirm whether the extra spend buys something you will notice in weekly use.

Where to Check Deals

Check current deals on Amazon and eBay using the buttons below — listing prices, seller quality, and condition can change quickly.

Check current deals on Amazon and eBay

Prices change often, so compare the latest listings and condition options before you buy.

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Seiko Prospex

Check Price on AmazonOpens in new tab · Price may vary

Check Price on eBayFrom $998 · Live listings

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Seiko Prospex

Check Price on AmazonOpens in new tab · Price may vary

Check Price on eBayFrom $550 · Live listings

Affiliate links — WatchCompared earns a commission on qualifying purchases. This doesn't affect your price.

Comparison FAQ

Which one is better for smaller wrists?

Start with case width and lug-to-lug. The watch that looks smaller on paper is often the safer choice, but lug shape and thickness still affect how it wears.

Which is better for swimming or rough daily wear?

Use the water resistance row as the first filter. Higher ratings generally give more flexibility for swimming and water exposure, but strap choice and overall condition still matter.

Should I choose based on price alone?

Price matters, but the better buy is the watch that matches your fit, feature priorities, and use case. Check live listings first, then decide whether the price gap actually changes the ownership experience.