Patek Philippe
Marta Ghiglione
Watch Technician
8月 2022

Diving watches: everything you need to know about their water resistance

If the timepiece you wear on your wrist is a diver’s watch, or a water-resistant watch, the thought of diving into the sea, enjoying a moment of relaxation and fun, is certainly one of the most frequent in the summertime. But how to properly care for your watch in contact with water?
With the arrival of the summer season, the chances of your timepiece getting wet are more frequent: swimming, diving, snorkelling, sailing, surfing, etc., wherever you want to spend your holiday, it is good to leave with the knowledge of whether or not you have a diver’s or water-resistant watch.

Diving watches: some curiosities

One of the first diver’s watches was the Blancpain Fifty Fathoms. Launched back in 1953 as the first modern diver’s watch for military use adopted by the Canadian/French navy.
All these Fifty Fathoms models are intended to pay tribute to the pioneers of diving who, through their passion and devotion, expanded the horizons for underwater exploration. They inspired Blancpain to introduce innovative materials by pushing the limits of this timepiece further and further to meet the most particular needs related to professional underwater use.
Interestingly, the Fathoms is the unit of measurement used by divers: one Fathoms corresponded to one arm.
One of the most iconic and unique models in my opinion is available in the Pisa Orologeria flagship store: it is a Fifty Fathoms Bathyscaphe Chronograph Flyback, with a 42 mm case made entirely of steel with a 30 atm seal.

Diving watches: everything you need to know about their water resistance

Waterproof and water-resistant watches: the differences

There really is a difference between diver’s watches and water-resistant watches. Watches are only considered diver’s watches when they can withstand a pressure of at least 10 bar (100 metres), whereas water-resistant watches are resistant to less pressure and are therefore not recommended for diving.
The water resistance of a watch is expressed in bars, atmospheres or metres and water resistance is generally indicated on the back of a watch or on the dial:

  • Water resistance to 3 bar (or atm, 30m) is very low and can withstand rain, sweat and accidental water splashes when washing hands.
  • Water resistance to 5 bar (or atm, 50m) must be subjected to limited water pressure. You can therefore shower, bathe and swim.
  • Water resistance to 10 bar (or atm, 100m) means 100% waterproof watches. If you own a model of this seal, you can safely enjoy free swimming or even other water sports such as snorkelling or free diving, up to about 10 metres.
  • Water resistance to 20 bar or 30 bar (or atm, 200 m/300 m). This is a professional diver’s watch. As it is characterised by a high level of water resistance, it can be used during professional scuba diving.

Here are some guidelines for understanding the water resistance classification of a watch:

Diving watches: everything you need to know about their water resistance
Diving watches: everything you need to know about their water resistance

Proof of impermeability: who to contact

To test the water resistance of your timepiece, you need to turn to the Watchmaking laboratories. In our laboratory at the Flagship store in Via Pietro Verri, 7, we have professional machines that indicate within a few minutes whether your watch is water-resistant or a real waterproof watch.

What are seals and why do they make a watch waterproof?

Seals are put on to protect the watch from water, dust, perfume, dirt, and other elements to which the watch is exposed; they protect the internal components. It is a good habit to have them replaced consistently every 5/6 years before they deteriorate over time and cause water or moisture to enter.

Maintenance tips for diving watches

Before diving into water, we always recommend that you make sure that the winding crown is securely tightened on the case of your timepiece. After any contact with salt water, it would be a good idea to rinse well in fresh water at room temperature in order to remove the saltiness from the watch.

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