Is 38 mm a good size for a dive watch?

Yes. Size and water resistance are separate questions. The Antarctic Diver and the Aquamar measure 38 mm and are rated to 20 ATM, or 200 m.

What is the most water resistant Nivada Grenchen watch?

The Depthmaster, rated to 100 ATM, or 1,000 m, in a 39 mm case.

Which movement is inside the Antarctic Diver, the Aquamar and the Depthmaster?

All three use the Swiss Soprod P024 automatic, with a 38-hour power reserve.

Oct 30, 2026

38 and 39 mm Dive Watches: How to Choose the Right Size

Buying guide · 5 min read

A compact dive watch has a case of about 36 to 39 mm, rather than the larger cases many modern divers use. Nivada Grenchen makes three divers in 38 and 39 mm: the Antarctic Diver and the Aquamar at 38 mm with 20 ATM (200 m) water resistance, and the Depthmaster at 39 mm with 100 ATM (1,000 m). All three run on the Swiss Soprod P024 automatic movement. This guide explains how to read the size of a dive watch and which of the three fits which use.

In short

Antarctic Diver, 38 mm: the 1960s diver design, with or without a date.
Aquamar, 38 mm: a sandwich-style dial with two-tone lume, and a date on the Aquamar Vintage.
Depthmaster, 39 mm: the deep-water option, rated to 1,000 m.

In this guide

Why case size is more than the diameter
The 38 and 39 mm divers at a glance
Antarctic Diver, 38 mm
Aquamar, 38 mm
Depthmaster, 39 mm
How to choose your dive watch

Why case size is more than the diameter

The diameter printed on a product page is only one of four numbers that decide how a watch wears. Before choosing a diver, look at all four.

DiameterThe width of the case, measured without the crown. On a diver, the rotating bezel usually defines it.

Lug to lugFrom the tip of the top lugs to the tip of the bottom lugs. If it is wider than the flat top of your wrist, the lugs overhang, whatever the diameter.

ThicknessFrom the caseback to the top of the crystal. A double-domed sapphire crystal adds height at the centre while keeping the edges slim.

Lug widthThe width of the strap or bracelet at the case. All the watches in this guide have a 20 mm lug width.

Technical drawing of the 38 mm Nivada Grenchen Antarctic Diver with its diameter, 45 mm lug to lug, 12.9 mm thickness and 20 mm lug width — The Antarctic Diver: 38 mm wide, 45 mm lug to lug, 12.9 mm thick, 20 mm lug width.

The Nivada Grenchen 38 and 39 mm divers at a glance

Antarctic Diver

Diameter: 38 mm
Thickness: 12.9 mm
Water resistance: 20 ATM / 200 m
Movement: Soprod P024 automatic
Date: With or without date

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Aquamar

Diameter: 38 mm
Thickness: 12.9 mm
Water resistance: 20 ATM / 200 m
Movement: Soprod P024 automatic
Date: Date on the Aquamar Vintage

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Depthmaster

Diameter: 39 mm, 47 mm lug to lug
Thickness: 13 mm
Water resistance: 100 ATM / 1,000 m
Movement: Soprod P024 automatic
Date: No

Discover

The Soprod P024 is a Swiss automatic movement with a 38-hour power reserve. Every model above has a screw-down crown and a sapphire crystal.

Antarctic Diver, 38 mm

The Antarctic Diver brings the dive version of the Antarctic line into a 38 mm steel case, 12.9 mm thick. Its rotating black ceramic bezel carries luminous markers, and the hands and indexes are filled with Super-LumiNova. It comes with a date at 3 o'clock or as a no-date version, which keeps the dial symmetrical.

Nivada Grenchen Antarctic Diver, a 38 mm dive watch with black dial and rotating bezel, worn on the wrist — The Antarctic Diver, 38 mm, water resistant to 200 m.

Protection comes from a screw-down crown and a double-domed sapphire crystal, for 20 ATM, or 200 m, of water resistance. The watch is worn on a 20 mm strap or bracelet, tapering to 16 mm at the buckle, including the beads-of-rice bracelet and the Tropic rubber strap. See the Antarctic Diver collection.

Aquamar, 38 mm

The Aquamar shares the 38 mm, 12.9 mm case and the 20 ATM rating of the Antarctic Diver, with the same black ceramic bezel and a closed steel caseback engraved with a penguin and a gold medallion. Where it differs is the dial: a matte lacquered sandwich-style dial, with luminous indexes in two tones.

Nivada Grenchen Aquamar Vintage, a 38 mm dive watch with a blue and grey dial and black ceramic bezel — The Aquamar Vintage and its dark blue and grey dial.

The Aquamar Vintage uses a dark blue and grey dial taken from a design found in archives, and adds a date to the Soprod P024. The Aquamar is also available with a blue, grey or black dial.

Depthmaster, 39 mm

The Depthmaster is the deep-water option. Its 39 mm cushion case measures 47 mm lug to lug and 13 mm thick, and it is water resistant to 100 ATM, or 1,000 m, with a screw-down crown and an automatic helium escape valve. The unidirectional steel bezel of the Art Deco Depthmaster turns in 120 clicks and carries a 15-minute graduation. Its matte black dial uses the "Art Deco" numerals 3, 6, 9 and 12 with Super-LumiNova.

Nivada Grenchen Art Deco Depthmaster, a 39 mm dive watch water resistant to 1,000 m, worn on the wrist — The Art Deco Depthmaster, 39 mm, water resistant to 1,000 m.

The bronze versions use a CuAl8 copper-aluminium bronze case with a 316L steel caseback, a black ceramic bezel insert and a helium escape valve. Bronze develops a patina that depends on the wearer's environment and skin, and that patina can be polished back to the original colour. The full range, including a 42 mm Art Deco Depthmaster, is in the Depthmaster collection.

Nivada Grenchen Depthmaster Bronze with a CuAl8 bronze cushion case and black ceramic bezel — The Depthmaster Bronze cushion case.

How to choose your dive watch

You want the original 1960s diver lookThe Antarctic Diver, with or without a date.

You want a sandwich dial and a dateThe Aquamar Vintage.

You swim, snorkel or dive often and want the highest ratingThe Depthmaster, at 1,000 m.

A practical rule: measure the flat top of your wrist from edge to edge, then compare it with the lug to lug figure. If the lug to lug is shorter, the watch will sit inside your wrist.

Browse the collections, or see every Nivada Grenchen diver, from 38 to 42 mm, in our Swiss dive watches collection.

Antarctic Diver Aquamar Depthmaster Swiss dive watches