The Zodiac Aerospace GMT

The Zodiac Aerospace GMT


After the success of the Sea Wolf, Zodiac introduced the Zodiac Aerospace GMT using essentially the same case, with a 24 hour bezel which could rotate in both directions.   The advertisement below shows the Aerospace GMT together with the Datographic Sea Wolf, and it is thought to have been introduced in about 1962.

Zodiac GMT: Zodiac Aerospace GMT


As the GMT had an extra 24 hour hand, the advertising theme for the GMT was “Twice as much time for your money”.

ad gmt: Zodiac Aerospace GMT

The advertisement reads:

ad gmt cont

The watch did not have a settable 24-hour hand, and the two hour hands were geared together, the 24-hour hand moving once round the dial in 24 hours.

The 24-hour hand should be just after the 2 or 8 position on the inner dial if the 12-hour hands read 4.30 or 16.30.

The rotating bezel allows setting of the GMT offset.


In the early 1960’s the Zodiac Sea Wolf acquired a date complication, and the Sea Wolf Datographic, model 722-916 was launched.   722 referred to the signed 17 jewel Zodiac calibre 70-72 automatic movement which was introduced in 1961.  The movement is hackset, and the calendar function is quickset (old style).

This very successful AS calibre, later with 21 jewels was produced under the Communautee Horlogere de Precision, and was also used by Doxa, Girard Perregaux, Favre-Leuba, and Eberhard & Cie. for their men’s automatics during the 1960s.

The calibre 75 had a 24-hour function and was used in the GMT.  Some GMT models had a 24 hour movement marked 70-72.

Later GMT watches used the calibre 75B with a quickset date function, and the Calibre 76.

Cal 70 zodiac


The first model is shown below and came with a polished plated bezel which rotated in both directions, and with a green triangle at 0/24.  The 24-hour hand was an arrow with lume in the arrow head, the hour and minute hands thin baton with lume tips, and the second hand was a thin pointer.


chrome aerospace gmt: Zodiac Aerospace GMT

Later bezels were patinated.

725-925 zodiac: Zodiac Aerospace GMT

Image courtesy:

Both white and black dial versions were available.

forst gmt zodiac: Zodiac Aerospace GMT

The case back was engraved, ZODIAC,  WATER & SHOCK RESISTANT, AUTOMATIC – ANTIMAGNETIC – SWISS.   There was a scale logo opposite the ZODIAC logo, see below.

Later models were waterproof to 20 Atmospheres as was the Datographic Sea Wolf which used the same case.


aerospace case back: Zodiac Aerospace GMT

Early models were fitted with Cal. 70-72 or Cal. 75 movements, a Cal. 70-72 is shown below.

cal 70-72 GMT aerospace

The case is 35mm (excluding crown) 38mm (inclusive), a slim watch at only 11mm thick.  Snap down case back.

A Cal. 75 movement is shown below.

cal 75 zodiac: Zodiac Aerospace GMT

An early model with a 2 tone bexel is shown in its original case and $110 price tag.  The second hand on this watch is thought to be a replacement.

Aerospace GMT

The watch from the side showing the crown and milled bezel.

gmt aerospace

AERONAUT 752-925

The same model number was used for the virtually identical Aeronaut, except that Aeronaut replaced Aerospace GMT on the dial.

The hands on both models are those used on the Aerospace Jet 758.  Zodiac launched a line of 24 hour watches in 1962 as the Zodiac Hermetic. Over the years, the named changed to the Aeronaut Jet and finally to the Aerospace Jet.

Given the history of name changes for the Hermetic, it is probable that the Aeronaut name was superseded by the Aerospace GMT.  However, the Aeronaut used the Cal. 75 movement.

Zodiac Aeronaut

The model number and case back were identical to the (later?) GMT.

aeronaut case back: Zodiac Aerospace GMT

This model also came in white and in black dials.

aeronaut in black: Zodiac Aerospace GMT

The 1962 Zodiac Hermetic with the same hands as the Aerospace GMT, is shown below.  This has Cal. 721.

This was Zodiac’s only 24 hour watch, and the dial is deep black combined with red markers for the odd hours and Arabic numerals for the even hours.  This watch has a snap caseback which features the water-resistant system that was similar to the one found in the Sea-Wolf. This feature explains the name “Hermetic” as well as the fish engraved on the case back.  The fish is where the scales are engraved on the Aerospace case back.

hermetic about 1962: Zodiac Aerospace GMT




Later, the dial changed to one with baton hands, with longer pencil lume inserts, and a rectangular red 24-hour hand with a lume tip.   The case back with the scale logo continued.

The indexes remained narrow but now had lume dots on the inside.  The indices at 6, 9 and 12 were fluted.

A crossover model is shown below with the new hands, but the old 24-hour hand.

crossover gmt: Zodiac Aerospace GMT

Image courtesy: Hobart Town Antiques

The patinated bezel model is above, and the polished bezel below.

second gmt: Zodiac Aerospace GMT


gmt zodiac

The original case back with the engraved scale logo continued, a model with an engraved case back is shown below.

scales case back gmt: Zodiac Aerospace GMT

The case back later changed to the 20 atmosphere diving version, with Aerospace beneath Zodiac.

gmt v 2

20 atm case back


This is the same as the Sea Wolf case back with Aerospace instead of Sea Wolf.

Black dial versions are more common.  Thin pointer second hands were used.

Kaplan gmt

Image courtesy: Kaplans Auctioneers

The Kaplans catalogue reads :

ZODIAC, Aerospace GMT, Ref no. 752-925, men´s wristwatch, 35 mm, steel, self winding, plastic crystal, date, 24-hour indicator, original bracelet, foldingclasp, Ref no. /9, approx 1965.

A two tone bezel model was also available.  Below with white dial.

752-925 zodiac

And a black dial version.

Zodiac GMT



Then the model changed to wider indices and a sweep second hand with a rectangular lollipop.  Some models continued to use the scale engraved case back.   A white dial version is shown below.

first edition zodiac gmt

Below is a black dial version.

gmt aerospace zodiac

10k solid gold bezel version.

gold cap GMT

Photo credit Omega forum user: bigdubnick

And, a black dial version with bezel numbering in 2 shades.

zodiac GMT



Around 1968 the bakelite bezel was used on the 752-934 series.   The Cal 75 movement was used.   The wide indices continued.  Later the Cal 75B and Cal 76 movements were used and the case back was engraved 752-934B.  this was also referenced model number 1975W.

A model with a grey/black bezel and the original stretch band is shown below.

752 - 934 zodiac: Zodiac Aerospace GMT


Zodiac Aerospace GMT

934 case back: Zodiac Aerospace GMT

Images courtesy Watchuseek user : tomvox1

A variety of bezel combinations are shown below, all with a black dial.

gmt zodiac blue black

blue black gmt

grey gmt: Zodiac Aerospace GMT

red gmt

Perhaps the most coveted is the Pepsi dial.

pepsi gmt: Zodiac Aerospace GMT

Cal. 75B

75b cal

The 752-934B model had wider and flatter indices.

934B: Zodiac Aerospace GMT

Cal. 76

cal 76: Zodiac Aerospace GMT

934b case back

Images courtesy Omega forum user: jinson


Then the 752-934B became a World Time model as shown on the right below.

Cal 75B continued to be used in the same case with Aerospace still engraved on the case back.     Below is a comparison between the -934 models, together with a contemporary Zodiac Sea Wolf in the same case..

The World Time has a grey dial and 1 ring of cities on the bezel.

group shot: Zodiac Aerospace GMT

Image Omega Forum user: bigdubnick

Later models had 2 rings of cities on the bezel.

zodiac world time: Zodiac Aerospace GMT

Photo IG: @augustyn


world time: Zodiac Aerospace GMT

A NOS world time in the original box, marked Water Resistant.

2019 Release ZO9400/1

In 2019 Zodiac released the ZO9400 in 2 different dial types, each in a limited edition of 182 pieces.

This reimagined, limited edition has a ETA2893-2 automatic GMT movement.

Just as for the initial model, this release uses the current Super Sea Wolf case, except that the lugs are chamfered and the bezel is reworked.






There are few Zodiac Aerospace GMT models around and any of the models would be an asset to any collection.

The grail would be the 752-934 complete set, with 2 tone bakelite bezel.

752-934 complete set

Perhaps even a Pepsi dial!

pepsi aerospaceaerospace stuff

Images courtesy Uhrforum user: mgvogt