Rolex UK Military Codes: WW II to 80s Reference
Reference Guide

Rolex UK Military Codes: WW II to 80s Reference

By marcello pisani · Aug 5, 2025 · 31 replies
marcello pisani
WPS member · Rolex forum
31 replies11226 views1 photos
f 𝕏 in 💬 ✉ 🔗

Marcello Pisani, a respected voice in the horological community, shares an invaluable resource for collectors and enthusiasts: a detailed guide to UK military watch codes. Originally published in the Italian magazine Orologi & Market, Pisani's work deciphers the often-misunderstood engravings found on timepieces issued to British forces from World War II through the early 1980s. This article serves as a foundational reference, illuminating the historical context and specific markings that define these robust military watches.

31 collectors discussing this on the WatchProSite forumJoin the Conversation →
Here is the English translation/upgrade of a work about UK military codes   I originally wrote some years ago for the Italian magazine Orologi & Market.

 

This subject would deserve a medium-size book; however, I think it is interesting to share   some basic information, particularly referring to military watches delivered to UK Forces from the 1950s on.

 

In the short space of a single work it is impossible to describe all possible situations and every peculiar case.   Owners of eventual exceptions are kindly requested to share them.

 

WWII and Earlier Engravings

 

1) British Army

 

"The British Army has carried the 'Royal' designation since its establishment in 1661 by Charles II following the restoration of the monarchy. Individual regiments and units may earn additional 'Royal' honors for distinguished service, but the army itself has been 'Royal' since its founding."

 
       
  • WWW=Waterproof Wrist Watch, followed by a manufacturer letter (K=Timor, Y=Omega, F=Longines). Sometimes the manufacturer’s name was also engraved.
  •    
  • The Broad Arrow (stylized arrow marking Crown property).
  •    
  • One or two digit series showing the delivery and sometimes case number.
  •  
 
↑ Broad Arrow WWWK8211 (delivery number)36791 (case number)  
 

2) Royal Air Force

 
       
  • Broad Arrow.
  •    
  • Abbreviations: 6B, 6BB, 6A, or 6E, followed by a model/type number.
  •    
  • Year of delivery and progressive assignment number.
  •    
  • Sometimes “AM” (Air Ministry) instead of Broad Arrow on WWII deliveries.
  •  
 
AM6B/15910233/40  
 

Important: Delivery numbers were continuous each year — not restarted from 001.   If the last in 1945 was 6431, then the first in 1946 was 6432. This applied to all UK Forces.

 

3) Royal Navy (including Royal Marines and Fleet Air Arm)

 
       
  • Broad Arrow.
  •    
  • HS=Hydrographic Service (also used for Royal Marines and other branches).     
             
    • HS 9=wrist chronograph
    •        
    • HS 10=diver’s watch
    •      
       
  •    
  • Progressive assignment number and/or case number.
  •  
 
↑ Broad ArrowHS 10 CD (Clearance Diver)942.115  
 

Hybrid Engravings (1950s–1960s)

 

From the early 1950s, many casebacks carried numbers often wrongly described as NATO codes.   These were actually hybrids, mixing national MOD codes with NATO species codes:

 
       
  • 0552=MOD code for Royal Navy
  •    
  • W10=MOD code for British Army
  •  
 

Example: Omega “Fat Arrow”

 
6645-1010006B-5426850/53  
 

Example: RN Hamilton Chronograph

 
0552/924-33061720/72  
 

Example: RAF Hamilton Chronograph

 
6BB-5511860/72  
 

NATO Stock Number Era (mid‑1960s onward)

 

The NATO Stock Number (NSN) was created for precise classification of all NATO supplies. It has 13 digits:

 
       
  • First 4 digits=species code (6645=wristwatches).
  •    
  • Digits 5–6=country code (99=UK, 12=Germany, 14=France, 15=Italy).
  •    
  • Final 7 digits=random item code, progressive, with no inherent meaning.
  •  
 

Examples:

 
British Army Smith (1970)NSN: 6645-99-961-4045W10-6645-99-961-40451579/70  
 
Omega SM300 / Rolex MilsubNSN: 6645-99-923-7697W10-6645-99-923-7697288/67  
 
Royal Navy Rolex 55130552-923-7697199/74  
 
Royal Navy Omega SM3000552-923-7697577/70  
 

Footnote: Up to the present day there is no proof that progressive delivery numbers ever restarted   each year at a lower value than the last number issued the previous year.

 
    UK Military Code Example 

Key Points from the Discussion

Advertisement
The Discussion
DR
DrStrong
Dec 20, 2013

if I remember well, you have a very nice military Omega Sm300 ;-)

AM
amanico
Dec 20, 2013

Huge Thanks, my friend... By the way, Marcello, do you happen to know what " AM " stands for on a Blancpain Fifty Fathoms from 1967 / 1968??? Best, Nicolas

MA
marcello pisani
Dec 20, 2013

not certainly " Air Ministry " as this < AM > is an engraving made at the Blancpain factory . this abbreviation appears only on some Milspec1 and not on other FF ( AFAIK ) and neither on TR 900. the 3 digits figure is in my opinion the case number . honestly I have no clear ideas about the " AM " meaning .....

AM
amanico
Dec 20, 2013

Yes, like this one. I tried hard to find something about the true meaning of AM, in vain.... Thanks, Nicolas

MA
marcello pisani
Dec 20, 2013

I have seen another 2 or 3 with the same abbreviation .. all with very low case numbers ( under 1000 if I remember well ) ... worths study some more ...

AM
amanico
Dec 20, 2013

Then, I know the 38, the 57, the 80 and another one, whose SN has been totally scratched.... Very rare version, for sure! Best, Nicolas

Advertisement

Continue the conversation

This thread is active on the Rolex forum with 31 replies. Share your knowledge with fellow collectors.

Join the Discussion →