Seiko Prospex SPB155 (Baby Alpinist) vs Traska Freediver III

Side-by-side comparison of specifications and features

SeikoProspex

SPB155 (Baby Alpinist)

TraskaFreediver III

Freediver-III

Key Differences

Best Value

Seiko Prospex (Ref. SPB155 (Baby Alpinist))

Starting from $494

Slimmest

Seiko Prospex (Ref. SPB155 (Baby Alpinist))

12.9mm thick

See Both Watches on Your Wrist

Set your wrist circumference to compare relative case presence. Lug-to-lug is included when the catalog has it.

Your wrist

Medium (6.7″)

Watch A

Seiko Prospex SPB155 (Baby Alpinist)

Balanced

Round · 38mm · 46mm lug-to-lug

Optimal proportions for most wrists

Case: 38mmLug-to-lug: 46mmThickness: 12.9mm

Open this size in the full fit chart →

Watch B

Traska Freediver III

Balanced

Round · 39.8mm · 47.8mm lug-to-lug

Optimal proportions for most wrists

Case: 39.8mmLug-to-lug: 47.8mmThickness: 13.2mm

Open this size in the full fit chart →

Proportional guide only: wrist shape, strap articulation, bezel design, and case curvature change how a watch actually wears.

Price Comparison

Seiko Prospex

MSRP

$725

New

$494

Used

$372

Traska Freediver III

MSRP

$735

Used

$600

MSRP New (Amazon) Used (eBay)

Comparison of Seiko Prospex, Traska Freediver III
Specification	Seiko Prospex	Traska Freediver III
Pricing
MSRP	$725	$735
New Price	$494	N/A
Used Price (Low)	$372	$600
Used Price (High)	$2,250	$745
30-Day Trend	↑ +7.2%	0.0%
Used Price Range	$372 - $2,250	$600 - $745
Identity
Reference	SPB155 (Baby Alpinist)	Freediver-III
Nickname	N/A	N/A
Style	Field, Sports, Tool	Diver, Tool
Release Era	2010s	2020s
Dimensions
Diameter	38mm	39.8mm
Thickness	12.9mm	13.2mm
Lug Width	20mm	20mm
Lug to Lug	46mm	47.8mm
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	Fixed	Unidirectional rotating
Dial
Dial Color	Green	Black
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

Which Should You Buy?

Seiko Prospex SPB155 (Baby Alpinist) and Traska Freediver III can look close on a spec sheet, yet the tradeoffs that matter most are usually field character versus diver versatility. They both touch the tool use case, so smaller spec differences can matter more than brand preference.

Bottom line

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. Choose Seiko Prospex SPB155 (Baby Alpinist) if you are specifically shopping for a field style watch; choose Traska Freediver III if you are specifically shopping for a diver style watch.

Choose Seiko Prospex SPB155 (Baby Alpinist) when

Seiko Prospex SPB155 (Baby Alpinist) is a better fit for smaller wrists, mechanical-watch enthusiasts, field styling.

Choose Traska Freediver III when

Traska Freediver III is a better fit for buyers who want more wrist presence, mechanical-watch enthusiasts, diver styling.

Key Differences

Movement and upkeep

Seiko Prospex SPB155 (Baby Alpinist): automatic movement

Traska Freediver III: 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 SPB155 (Baby Alpinist): 38mm · L2L 46mm · 144g

Traska Freediver III: 39.8mm · L2L 47.8mm

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

Water resistance

Seiko Prospex SPB155 (Baby Alpinist): 200m

Traska Freediver III: 200m

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

Price and value

Seiko Prospex SPB155 (Baby Alpinist): $494

Traska Freediver III: $735

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 SPB155 (Baby Alpinist): field

Traska Freediver III: diver

Seiko Prospex SPB155 (Baby Alpinist) leans more field, while Traska Freediver III pulls toward diver use case — pick the one that matches how you will actually wear it.

Crystal and materials

Seiko Prospex SPB155 (Baby Alpinist): sapphire crystal · steel

Traska Freediver III: sapphire crystal · steel

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

Why These Watches Are Often Compared

Seiko Prospex SPB155 (Baby Alpinist) and Traska Freediver III get compared constantly because both are tool watches, they are within 1.8mm of each other in case width, they share the same automatic movement — so the spec sheet alone will not tell you which to buy.

The Differences You Will Notice in Daily Use

Lug-to-lug is 46mm on Seiko Prospex SPB155 (Baby Alpinist) and 47.8mm on Traska Freediver III; that, more than case width, decides whether it overhangs a smaller wrist.
Seiko Prospex SPB155 (Baby Alpinist) is around $494 and Traska Freediver III around $735 — about a $241 gap at typical listings.

Which One Should You Buy

Seiko Prospex SPB155 (Baby Alpinist) for most buyers — Lug-to-lug is 46mm on Seiko Prospex SPB155 (Baby Alpinist) and 47.8mm on Traska Freediver III; that, more than case width, decides whether it overhangs a smaller wrist.

Choose Seiko Prospex SPB155 (Baby Alpinist) If...

You are specifically shopping for a field style watch.
You want the lower current entry price.

Choose Traska Freediver III If...

You are specifically shopping for a diver style watch.
You are comfortable paying more for a stronger feature set.

Price and Value Notes

Seiko Prospex SPB155 (Baby Alpinist) is often the value play at current pricing, while Traska Freediver III 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 $639 · New & used listings

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Traska Freediver III

Check Price on AmazonOpens in new tab · Price may vary

Check Price on eBayFrom $675 · New & used 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?

Seiko Prospex SPB155 (Baby Alpinist) — it is 46mm lug-to-lug versus 47.8mm, and lug-to-lug is what decides whether a watch overhangs a smaller wrist.

Which is better for swimming or rough daily wear?

They are rated the same, so water resistance will not decide this. Choose on strap material and how much you mind scratching the case.

Is the more expensive one worth it?

Seiko Prospex SPB155 (Baby Alpinist) is the value pick at roughly $241 less. Pay more only if a specific difference above matters to you — otherwise the cheaper one is the smarter buy. Confirm live listings, since marketplace pricing moves.

What is the actual difference between Seiko Prospex SPB155 (Baby Alpinist) and Traska Freediver III?

Lug-to-lug is 46mm on Seiko Prospex SPB155 (Baby Alpinist) and 47.8mm on Traska Freediver III; that, more than case width, decides whether it overhangs a smaller wrist. That is the difference you will notice day to day; the rest of the specs are close enough not to matter.

Which one should I buy?