Black Bay 54

Ref. M79000N

Case diameter: 37 mm; Manufacturer spec
Lug-to-lug: 46 mm; Measured in a published review
Thickness: 11.2 mm; Measured in a published review
Lug width: 20 mm; Measured in a published review

Retail price $4,725 (US, Oct 2026)

Your wristIdeal fit

Wrist flat: 55.1 mmLug-to-lug: 46 mm

How the Black Bay 54 wears

Its lugs reach 9 mm past the 37 mm case, more than the 7.1 mm typical across the almanac, so it wears larger than its diameter suggests.

On our fit model it sits best on wrists from 6.5" to 7.75" (16.5–19.7 cm); below 6.5" the lugs start to reach the edge of the wrist.

At 11.2 mm thick it is slimmer than 97% of the 79 other dive watches we've measured, so it slides under a cuff more easily than most.

Its 20 mm lug width is one of the most common strap sizes; 104 other watches here share it, so aftermarket straps are easy to find.

Will the Black Bay 54 fit your wrist?

With a 46 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	Snug, lugs near the edge
6.5"	51.2 mm	Ideal fit
7"	55.1 mm	Ideal fit
7.5"	59.1 mm	Ideal fit
8"	63 mm	Wears small

Specifications

Reference: M79000N
Collection: Black Bay 54
Status: In production
Introduced: 2023
Case material: stainless steel
Crystal: sapphire
Water resistance: 200 m
Bezel: unidirectional 60-minute, aluminium insert without minute graduations
Dial: black
Strap / bracelet: 3-link steel bracelet, T-fit clasp
Style: Dive