Seiko Prospex SPB143 vs Marathon TSAR

Both are dive watches in the upper tier. In short: the Seiko Prospex SPB143 is mechanical (automatic) for the enthusiast feel and no battery; the Marathon TSAR is quartz for accuracy and low maintenance. The Seiko Prospex SPB143 is automatic, 200m water resistance, 40.5mm, sapphire crystal; the Marathon TSAR is quartz, 300m water resistance, 41mm, sapphire crystal.

Last verified 2026-06-27 · specs from manufacturer data · tier = price band, confirm the live price at the retailer

Spec	Seiko Prospex SPB143	Marathon TSAR
Movement	Automatic	Quartz
Water resistance	200m	300m
Case size	40.5mm	41mm
Crystal	sapphire	sapphire
Style	Dive	Dive
Price tier	Upper	Upper

Which should you buy?

The Seiko Prospex SPB143 is mechanical (automatic) for the enthusiast feel and no battery; the Marathon TSAR is quartz for accuracy and low maintenance
The Marathon TSAR takes more water (300m) — both are fine for swimming, but it has more margin if you dive

Where to buy

Seiko Prospex SPB143See price on AmazonCheck price

Marathon TSARSee price on AmazonCheck price

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FAQ

What's the difference between the Seiko Prospex SPB143 and the Marathon TSAR?
Both are dive watches in the upper tier. The Seiko Prospex SPB143 is automatic, 200m water resistance, 40.5mm, sapphire crystal; the Marathon TSAR is quartz, 300m water resistance, 41mm, sapphire crystal.

Which has better water resistance, the Seiko Prospex SPB143 or the Marathon TSAR?
The Marathon TSAR, rated 300m, versus 200m on the other. Pick 100m or higher for swimming and 200m+ for diving.

Which is better value, the Seiko Prospex SPB143 or the Marathon TSAR?
Both sit in the upper tier, so it comes down to movement, water resistance and case size — see the spec table above.

Citing these specs? Go ahead — manufacturer data, last verified 2026-06-27. Copy a ready-made reference:

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