Serial number resource guide.

“Round Number” Serial Number List

*(At this time Rolex started the numbering system back at 10000. This time period also saw the start of the “Roman Numeral” dating system explained above.)

**(Start of the letter prefix system.)

***Also started engraving the serial number inside the bezel (under the crystal)

****(Now features 8-digits instead of 7)

“Round Number” Serial Number List

On the inside of the clasp hinge is a code that designates the month and year that the clasp/bracelet was manufactured. When examing watches at an AD or watch mart, do not be surprised if a bracelet is a few years older than the watch case. In modern Rolex watches, it is rare to find a clasp code that is the same year as the watch case.

On the clasp hinge is one or two letters followed by a number. The letters represent the year code, and the numbers signify the month. A clasp code of OP9 indicates the clasp/bracelet was manufactured in 2006, and the number indicates the month of September.


* (e.g. CX3, J4M, 5AM, etc)

S = Service: Clasp replaced during a “S”ervice.

On older United States paper certificates, there are red letters stamped on the certificate signifying when the watch shipped from Rolex USA to the Authorized Dealer (AD).

For example, a code of A OXCR represents 7 2591 or July 25, 1991

On watch certificates that are shipped with Non-United States Rolexes, there is a punched number in front of the serial number that signifies the country with which the watch was initially shipped by Rolex Geneva. These numbers come in handy when considering a grey-market watch to discern its where the watch was initially released.