Marathon GSAR vs Seiko Prospex

Side-by-side comparison of specifications and features

MarathonGSAR

WW194006

SeikoProspex

SPB143

Key Differences

Best Value

Seiko Prospex (SPB143)

Starting from $984

Best Water Resistance

Marathon GSAR (WW194006)

300m (2x more)

Biggest Price Drop

Seiko Prospex (SPB143)

-2.0% in 30 days

Price Comparison

Marathon GSAR

MSRP

$2,200

New

$1,890

Used

$1,339

Seiko Prospex

MSRP

$1,200

New

$1,399

Used

$756

MSRP New (Amazon) Used (eBay)

Comparison of Marathon GSAR, Seiko Prospex
Specification	Marathon GSAR	Seiko Prospex
Pricing
MSRP	$2,200	$1,200
New Price	$1,890	$1,399
Used Price (Low)	$1,339	$756
Used Price (High)	$3,849	$1,890
30-Day Trend	↑ +5.8%	↓ -2.0%
Used Price Range	$1,339 - $3,849	$756 - $1,890
Identity
Reference	WW194006	SPB143
Nickname	N/A	N/A
Style	Diver, Tool	Diver, Tool
Release Era	2010s	2020s
Dimensions
Diameter	41mm	40.5mm
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	300m (diving)	200m (diving)
Bezel	Unidirectional rotating	Unidirectional rotating
Dial
Dial Color	Black	Gray
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

This Marathon GSAR vs Seiko Prospex comparison is less about a universal winner and more about water-ready utility versus dressier everyday wear, 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.

Marathon GSAR

Marathon GSAR is a better fit for mechanical-watch enthusiasts, diver styling.

Seiko Prospex

Seiko Prospex is a better fit for mechanical-watch enthusiasts, diver styling.

Key Differences

Movement and upkeep

Marathon GSAR: automatic movement

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

Marathon GSAR: 41mm

Seiko Prospex: 40.5mm

Their size profiles are relatively close, so fit comes down to shape, weight, and how each watch sits on your wrist.

Water resistance

Marathon GSAR: 300m

Seiko Prospex: 200m

Water resistance is a meaningful separator here — the higher-rated option gives more flexibility for swimming or rougher daily use.

Price and value

Marathon GSAR: $1,890

Seiko Prospex: $984

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

Marathon GSAR: diver

Seiko Prospex: diver

Both lean into a similar diver use case — the choice is more about fit, features, and price than category.

Crystal and materials

Marathon GSAR: sapphire crystal · steel

Seiko Prospex: sapphire crystal · steel

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

Choose Marathon GSAR If...

Swimming, beach use, or tougher daily wear is part of the plan.
You are comfortable paying more for a stronger feature set.

Choose Seiko Prospex If...

You want the lower current entry price.

Price and Value Notes

Seiko Prospex is often the value play at current pricing, while Marathon GSAR 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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Marathon GSAR

Check Price on AmazonOpens in new tab · Price may vary

Check Price on eBayFrom $1693 · Live listings

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Seiko Prospex

Check Price on AmazonOpens in new tab · Price may vary

Check Price on eBayFrom $984 · 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.