Apple Watch Series 9 features the new S9 processor and a brighter display.

The S9 delivers increased performance and enables new capabilities, including the new double tap gesture. The watch detects the user tapping their index finger and thumb twice by applying a machine learning model to the data from the accelerometer, gyroscope, and optical heart sensor. This feature will be enabled in a software update scheduled for October.

Double tap controls the primary button in an app (eg, to stop a timer, or play and pause music), and it can be used to answer and end a phone call, take a photo with the Camera Remote, or open the Smart Stack and scroll through widgets in the stack.

The Apple Watch Series 9 has a 2000 nit display (twice as bright as the Series 8). This makes it easier to read in bright sunlight, but it can go as low as one nit in dark rooms to help avoid disturbing nearby people.

Another use for the increased power of the S9 is to process Siri requests on-device when they do not require information from the internet. Examples include setting a timer or starting a workout.

Furthermore, Siri can access data from the Health app, for example to tell the user how many hours of sleep they had the previous night, or to log health data such as weight or medications taken. Again, this feature requires a forthcoming software update.

S9 also includes Apple's second-generation Ultra Wideband chip for precision finding of similarly-equipped devices such as the iPhone 15 range, as well as improved integration with HomePod.

Despite these added features, Apple says the Series 9 still provides 18-hour battery life thanks to the power efficiency of the S9.

Alongside the Apple Watch Series 9, Apple has introduced its FineWoven bands "a luxurious and durable microtwill made of 68% post-consumer recycled content that has significantly lower carbon emissions compared to leather." The company no longer uses leather in any of its products.

The Apple Watch Series 9 can be ordered immediately, and will be available in-store from 22 September. Prices start at $649, with a choice of 41mm and 45mm cases. Aluminium cases come in starlight, midnight, silver or pink, while the stainless steel version com in gold, silver or graphite.

In addition, the Sport Loop band has been redesigned to incorporate 82% recycled yarn.

Apple Watch Ultra 2

Apple Watch Ultra 2 also uses the S9 processor and includes the features of the Apple Watch Series 9 with the addition of 36-hour battery life, a 3000 nit display – "the brightest display Apple has ever designed" – and a new Modular Ultra face that uses the outermost edge of the display to present real-time data, including seconds, altitude, or depth. On that last point, the new model has an operating range of 500m below sea level to 9,000m, and underwater to a depth of 40m.

Huish Outdoors' Oceanic+ app has been updated to take advantage of the Apple Watch Ultra 2.

Apple Watch Ultra 2 costs $1,399 and can be ordered immediately with availability from 22 September.

Apple Watch SE remains available, with list prices starting at $399.