Rolex T SWISS T  – What Does it Mean?

When Did Rolex Stop Using Tritium?

Rolex T SWISS T  and Swiss-T <25 – What Does it mean?

There are many small details on Rolex watches that you may not even pay a second thought to at first glance. Rolex is a company that is all about evolution, not revolution. As such, the company consistently improves and refines its products, making small tweaks of visual details, materials used, and technical improvements. All of this is to improve their durability, reliability, and overall performance.

But if you have looked at a Rolex watch and found the text ”T SWISS T” or ”Swiss-T <25”, or perhaps ”Swiss”, printed at the bottom of the dial at 6 o’clock, what does it mean?

The fact is that the different Swiss printings on the Rolex dials actually indicate something, and are not just there for decoration.

Rolex T Swiss T and other Swiss made dial printings

Rolex has used a number of different Swiss made printings on its dials over the years. And the printing actually relates to the luminous material used for the indices and hands.

In its early days, Rolex used radium paint for the luminosity of its watches. These early Rolex watches have ”SWISS” printed at the bottom of the dial at 6 o’clock. The catch is that Rolex would also later come to use the same printing again (more on that later). Radium, as you know is extremely radioactive and due to health concerns, and the introduction of new luminous materials over time, Rolex eventually replaced the radium paint

Swiss-T <25, T SWISS T, T Swiss Made T

Rolex replaced the radium with tritium, and the above markings were used on the radium watches to indicate such. The benefit of tritium is that it is not dangerously radioactive. It does, however, have a half-life of 12 years, which means that over the years, it will lose its glow.

Rolex used tritium up until the 1990s when it replaced it with yet another material. Rolex changed to luminova around 1999. Rolex used lumina for a relatively short period of time, and this can be seen with the watches that have ”Swiss” printed on the dial. These watches are referred to by collectors as ”Swiss only”, as they only feature the Swiss text.

Later on, Rolex changed to Superluminova, and now, Rolex has ”Swiss made” on all of its watches. However, in recent years, Rolex has started printing the logo coronet between Swiss and Made, to indicate that the watch has a second-generation movement.

So what do all of these dial prints mean?

“T Swiss made T”

This printing indicates that the watch uses tritium (T=tritium) and tells us that the tritium emits less than 227 MBq (7.5 mCi). This printing also indicates that the indices are made in gold.

“Swiss T<25”

This printing means that the watch emits less than 925 MBq (25 mCi) of radioactive radiation.

30 thoughts on “Rolex T SWISS T  – What Does it Mean?

  1. I bought a Rolex Datejust that looks great. It’s a model 16233 with a gold face and has the markings “SWISS MADE” below the 6 position. I don’t see this marking with capital letters in your article titled “Rolex T SWISS T – What does it mean”. WHY?

    1. Hello,
      Depending on when the watch was made, it may or may not have it. When it does not have the “T”, it means that it does not use tritium for the luminosity but instead luminova.

      Kind regards,
      Millenary Watches

    2. The term Datejust means that it is a Rolex knockoff. It may look and act the same as a Rolex but made by another company

  2. dobrý den zakoupil jsem hodinky wittnauer udajne cca 60leta pozlacene je možno vám poslat foto na posouzení příjde m ze natahování nenní origo děkujji moc DUfek

    1. Hello,
      You can order a consultation here:
      https://millenarywatches.com/watches/watch-consulting/

      Kind regards,
      Millenary Watches

  3. Hello. Thank you for posting this informative article.

    I have a model 1600 Datejust with serial 9xx,xxx that dates it to being manufactured in 1964. Below the 6 marker is: – SWISS –

    Was this indicative of Radium markers?

    Thank you.

    1. Hello,
      Yes that is correct.
      Although, Rolex stopped with Radium in the beginning of the 1960s, it is possible they had stock of dials left.

      Kind regards,
      Millenary Watches

  4. So what does T Swiss T mean?

    Your article title is “Rolex T SWISS T Meaning”, you mention it as a differentiator in the article, then at the bottom you only say what T SWISS MADE T and SWISS-T <25 mean?

    1. Hi,
      It is mainly a “symbol”, but essentially, you could say that it means Tritium Swiss Tritium. Meaning the watch uses tritium and is made in Switzlerland

      Kind regards,
      Millenary Watches

  5. Thanks for the information and hopefully you get to read this as I’d appreciate your expertise.

    I have a mid 90’s Datejust 36 salmon dial with Roman numerals. Engine turned bezel.

    Should this dial have the ‘T’ by the 6 o’clock to indicate the presence of the luminous material used back then?

    I have scoured images and some mid 90’s dials don’t have the ‘T’.

    My dial says ‘Swiss Made’, which apparently was used after Tritium was no longer used.

    I’ve been reading all about the luminous chemicals used over the decades etc.

    Did every dial made actually have the chemicals or were there some dials that it wasn’t required?

    Any information would be great.

    Regards, Julian.

    1. Hi,
      The watches that use tritium have T swiss T. But there are salmon dial versions (roman makrkers) without luminescence that have Swiss made only.

      Kind regards,
      Millenary Watches

  6. Thanks for your information. It answered my question since the first day my 16613 in hand in 1994.

    Thanks!

    1. Thanks for reading! Congratulations on a beautiful timepiece. Wear it in good health.

      Kind regards,
      Millenary Watches

  7. I’m looking at a Rolex and the bottom of the face says TT Swiss Made TT, with double T’s not singulars. Is this a sign of a fake?

    1. Hi,
      Not necessarily. The dial may be a replacement/custom dial and the rest of the watch may be authentic but it could be a sign that it is fake. But it is hard to say without having inspected it. I would recommend that you have it checked by a watchmaker or Rolex retailer.

      Kind regards,
      Millenary Watches

  8. Ours says T SWISS MADE T
    Also DATEJUST Seems same font as Rolex with OYSTER PERPETUAL Smaller. What years were the T SWISS MADE T made

    1. Hi,
      It completely depends on the model but during 1964 and 1967, watches were signed “Swiss – T<25” and “T-Swiss-T”.

      Kind regards,
      Millenary Watches

  9. The T Swiss T I was in the comments mean Tritium Swiss Tritium meaning use Tritium and made in Switzerland . Do you know how much Tritium is in them as the others have amounts MBq (mCi)

    1. Hi,
      Rolex has not specified how much tritium is used in the others. The only dial type that Rolex has specified the amount of tritium used is the Swiss – T <25 which indicates that there is less than 25 micro-curie. As for the others, the tritium content was higher, but it's not specified exactly how much.

      Kind regards,
      Millenary Watches

  10. I took my 1980’s model 36MM stainless / gold Rolex Datejust in for a replacement jubilee bracelet, and it was sent to Rolex. I received back a new dial as well that now no longer has the T SWISS MADE T dial – now just says SWISS MADE. Does this diminish the overall value of the watch (compared to original watch dial)?

    1. Hi,
      Yes, unfortunately, it does have a somewhat negative effect on the value. But perhaps not as much as on models that are more collectible than the Datejust. Collectors want everything to be in original condition and a replacement dial – just how it originally was. According to some, a replacement dial therefore negatively affects its appeal.

      Kind regards,
      Millenary Watches

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