Seamaster Planet Ocean 600M 42

Ref. 217.30.42.21.01.001

Case diameter: 42 mm; Manufacturer spec
Lug-to-lug: 47.5 mm; Manufacturer spec
Thickness: 13.8 mm; Manufacturer spec
Lug width: 21 mm; Manufacturer spec

Retail price $9,200 (US, Oct 2026)

Your wristIdeal fit

Wrist flat: 55.1 mmLug-to-lug: 47.5 mm

How the Seamaster Planet Ocean 600M 42 wears

Its lugs add only 5.5 mm to the 42 mm case, against 7.1 mm typical across the almanac, so it wears smaller than its diameter suggests.

On our fit model it sits best on wrists from 6.75" to 8" (17.1–20.3 cm); below 6.75" the lugs start to reach the edge of the wrist.

At 13.8 mm thick it is thicker than 78% of the 79 other dive watches we've measured, so expect it to sit tall on the wrist.

Its 21 mm lug width is one of the most common strap sizes; 28 other watches here share it, so aftermarket straps are easy to find.

Will the Seamaster Planet Ocean 600M 42 fit your wrist?

With a 47.5 mm lug-to-lug, here is how it wears across common wrist sizes. We estimate the flat top of each wrist from its circumference; measure yours for a closer answer in the fit finder.

Wrist	Flat width (est.)	Fit
6"	47.2 mm	Lugs overhang
6.5"	51.2 mm	Snug, lugs near the edge
7"	55.1 mm	Ideal fit
7.5"	59.1 mm	Ideal fit
8"	63 mm	Ideal fit

Specifications

Reference: 217.30.42.21.01.001
Collection: Seamaster
Status: In production
Case material: stainless steel
Crystal: sapphire
Water resistance: 600 m
Bezel: unidirectional rotating, black ceramic with white enamel diving scale
Dial: black
Strap / bracelet: steel bracelet
Weight: 177 g
Style: Dive

Movement

Caliber: Omega 8912
Type: automatic
Power reserve: 60 hours
Frequency: 25,200 vph (3.5 Hz)
Accuracy: 0/+5 s/day (METAS Master Chronometer)

Takes 21 mm straps. See other 21 mm watches and straps.

More Seamaster references

Watches that wear the same size

Other watches within 1.5 mm of its lug-to-lug.

Same 21 mm lug width

All 21 mm watches

These take the same straps as the Seamaster Planet Ocean 600M 42.