Apple Watch Series 12 ships with a depth gauge rated to 6 meters and a water temperature sensor, according to Apple’s tech specs page, sitting inside the same 50-meter water resistance rating the watch has carried for three generations. Apple Watch Series 12 reaches stores Friday, September 18, alongside Apple Watch Ultra 4 and iPhone 18 Pro.
The pairing is notable mostly for its history. Apple Watch Series 10 had a depth gauge and a water temperature sensor in 2024. Series 11 dropped both in 2025. Series 12 brings them back in 2026, which means the sensor has appeared, disappeared and reappeared across four straight generations of the standard Series line, something Apple has not explained.
The key numbers
What a depth gauge and a water temperature sensor actually measure
Apple’s tech specs page lists the depth gauge and water temperature sensor alongside the rest of Series 12’s sensor bank: a third-generation electrical heart sensor, an always-on optical heart sensor, a Blood Oxygen sensor, a temperature sensor, a compass, an always-on altimeter, a high-g accelerometer, a high dynamic range gyroscope and an ambient light sensor. A depth gauge reports how far underwater the watch currently is. A water temperature sensor reports the temperature of the water around it. Apple’s specs page does not attach an accuracy figure to either sensor on Series 12, and does not name a dedicated watch face, complication or app that displays the reading.
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On, off, and on again
Apple Watch Ultra 4 has carried a depth gauge in every generation of Ultra, rated for recreational scuba to 40 meters with an accuracy of plus or minus 1 meter on Ultra 2 and Ultra 3, inside a 100-meter overall water resistance rating under ISO 22810:2010 that Apple’s specs page also states covers swimming, snorkeling, scuba and high-speed water sports. Ultra 4 carries the same class of rating. That gap is why Series 12’s 6-meter figure and Ultra’s 40-meter figure describe two different sensors built for two different purposes rather than the same feature at different depths.
Why the 50-meter rating still sets the limit
A depth gauge only reports a number. It does not, on its own, change the watch’s overall water resistance rating. Series 12’s rating remains 50 meters under ISO 22810:2010, the same swimproof classification Series 10 and Series 11 carried, so the sensor’s return does not move Series 12 into the same water-resistance class as Ultra 4’s 100-meter, EN13319-certified rating. Apple’s own wording for the Series line’s rating covers swimming; its wording for Ultra names scuba diving specifically. The two are separate claims, not the same claim written at different depths. The rating and both sensors apply across all three case materials Apple sells this year, aluminum, titanium and ceramic, since Apple’s specs page does not list a water rating that changes by material.
What Apple has not said
Apple’s Series 12 specs page does not publish an accuracy figure for the depth gauge the way it does for Ultra 4’s plus-or-minus 1 meter claim, and it does not name a Series 12 feature that surfaces the water temperature reading to the wearer. Apple also has not said why the sensor pair was dropped for Series 11 in the first place, or whether it is now a permanent part of the Series line rather than a feature that comes and goes by generation.
Apple Watch Series 12 is available to pre-order now and reaches stores Friday, September 18, in the United States and more than 50 other countries and regions, per Apple’s announcement.
