watchOS 27 features: What’s new and what requires Series 12 or Ultra 4

Apple released a new version of the software that runs on the Apple Watch – watchOS 27 – on September 14, 2026, but not every new feature is available on every supported watch. Some improvements are software-led and work across compatible models, while others depend on the S11 chip and redesigned sensors in the Apple Watch Series 12 and Ultra 4.

The hardware-dependent health features unique to the 2026 Watches include background heart-rate measurements every five seconds and HRV (heart rate variability) measurements every five minutes. The Series 12 and Ultra 4 also gain the Readiness app, which analyzes recent activity, training load, sleep and health data to produce a daily recovery score. Other exclusives include daytime resting heart-rate and HRV data in Vitals, a real-time chart in the Heart Rate app, more accurate all-day step counting and a Steps complication that updates on the watch face.

The S11 chip also enables Apple’s Audio Intelligence features. Automatic Music Recognition uses Shazam to identify nearby songs and display them in the Smart Stack, while Sound Recognition can detect doorbells, alarms, sirens and crying babies without relying on the iPhone. Live Rewind displays a transcript of the previous 15 seconds of conversation after a double-press of the Digital Crown; it does not save an audio recording. Siri Recap produces high-level summaries of conversations. Live Rewind and Siri Recap are expected to arrive in beta later in 2026 and require a compatible Apple Intelligence iPhone and Siri AI.

Other watchOS 27 features are more widely available. These include the Dynamic App Grid, redesigned Find My app, menopause and perimenopause tracking, Call Context and Workout Buddy improvements. Apple has also introduced the Longevity section and Health Age.

Compatibility is considerably more restricted than it was with watchOS 26. Series 9 and Ultra 2 are now the oldest supported models, while the SE 3 is the only compatible SE. The Series 6, Series 7, Series 8, SE 2 and original Ultra cannot install watchOS 27. Anyone considering a discounted older Apple Watch should therefore choose a Series 9, Series 10, Series 11, Ultra 2 or Ultra 3 if receiving current feature updates is important. See: These Apple Watches are now obsolete.

Foundry

Consider your wrist size and comfort

The watch should feel secure without dominating your wrist or restricting movement. The 40mm SE 3 is the best option for particularly small wrists, while the 42mm Series 12 provides a larger display in a case that remains manageable for most people. If possible, try both sizes in an Apple Store before buying.

Consider display size and readability

A larger screen makes text, notifications and onscreen controls easier to see and use. The 49mm Ultra 4 has the largest display, but its 63g titanium case is substantially heavier than the aluminum Series 12 or SE 3. The 46mm Series 12 offers a spacious display without the Ultra’s additional bulk.

Consider whether you need the Ultra

Don’t choose the Ultra 4 solely because it has the largest screen. Its size makes most sense if you also need its rugged titanium construction, satellite connectivity, precision dual-frequency GPS, diving support or 50-hour battery life. For everyday use, the Series 12 will generally be more comfortable.

Check band compatibility

Apple Watch bands aren’t universally interchangeable. Bands designed for smaller cases generally fit the 38mm, 40mm, 41mm and newer 42mm watches, while larger bands work with 44mm, 45mm, 46mm and 49mm models. However, the older 42mm case belongs to the larger band family, so check the compatibility information before reusing or ordering a band.

Aluminum, titanium or ceramic: Which Apple Watch material is best?

Foundry

Another consideration when buying an Apple Watch is its case material, which affects its durability, weight, appearance and price. Apple currently offers aluminum, titanium and ceramic cases, although the available materials depend on the model.

Aluminum: Best for most people

Aluminum is the lightest and most affordable choice. It is the only material available for the Apple Watch SE 3 and the entry-level option for the Series 12, helping to keep their starting prices at $249 and $399 respectively.

It is a good choice for everyday wear, fitness and sleep tracking because it feels lighter on the wrist than the premium alternatives. The SE 3 uses Ion-X display glass, which Apple says is four times more crack-resistant than that of the SE 2. The aluminum Series 12 has the tougher Ceramic Shield 2 display, which Apple claims is 60 percent more durable than the Ion-X glass used by the aluminum Series 11.

Titanium: Best for premium durability

Titanium is available with the Series 12 and is the only case material offered with the Ultra 4. It provides a more premium finish and is paired with highly scratch-resistant sapphire crystal rather than the glass used on aluminum models.

The Series 12 titanium case is available in Natural or Radiant Gold. It is a good option for anyone who wants a more luxurious and durable everyday watch without moving up to the much larger Ultra.

The Ultra 4 uses a rugged Grade 5 titanium case in Natural or Black. It is designed for outdoor adventures, endurance sports and diving, with a 49mm case, 100-meter water resistance and recreational diving support. However, its size and 63g weight make it less comfortable for smaller wrists and sleep tracking.

Ceramic: Best for distinctive styling

Ceramic returns as a premium Series 12 option in Pearl White and Night Blue. It has a glossy, distinctive finish and uses a sapphire crystal display, but it is heavier and considerably more expensive than the aluminum version. The ceramic cases are also slightly larger than the other Series 12 configurations.

Which material is best for Apple Watch?

For most buyers, aluminum offers the best balance of price, durability and comfort. Choose titanium if you want a more premium finish, sapphire crystal or the Ultra 4’s specialized outdoor capabilities. Ceramic is primarily a style-led luxury choice for buyers who want the most distinctive Series 12 and are prepared to pay more for it.

Do I need a cellular Apple Watch?

Whether you need a cellular Apple Watch depends mainly on how often you plan to leave your iPhone behind. For most buyers, the answer is no: a GPS-only Apple Watch offers better value and can already do a great deal without an active connection to an iPhone.

Away from your iPhone, a GPS Apple Watch can still track workouts, monitor health, record location data, use Apple Pay and play music or podcasts downloaded to the watch. When connected to a known Wi-Fi network, it can also send and receive messages, make calls and use many online services. See our guide to Everything an Apple Watch can do without an iPhone.

Cellular becomes useful when you regularly leave your iPhone at home but still want calls, messages, music streaming, navigation and notifications. This makes it particularly valuable for runners, cyclists, swimmers and gym users who don’t want to carry a phone. It can also provide reassurance when you are walking alone or exercising away from Wi-Fi, because the watch can contact emergency services after a fall or crash using its own mobile connection.

A cellular model is also the right choice when setting up an Apple Watch for a child or older relative who doesn’t have an iPhone. Apple Watch For Your Kids, previously called Family Setup, allows a family member’s watch to be configured from another person’s iPhone. A cellular plan enables calls, messages and location sharing when the watch is away from the managing iPhone.

The drawbacks are cost and redundancy. A cellular Series or SE generally costs more than its GPS equivalent, and you must also pay your network provider a monthly fee. If your iPhone is nearly always in your pocket or bag, the watch will normally use its connection instead, leaving you paying for cellular service that you rarely need. See: I switched to a cellular Apple Watch to prove I didn’t need one.

Our recommendation: The Ultra 4 includes cellular as standard, so there is no GPS-only version. For the Series 12 and SE 3, choose cellular only if you expect to leave your iPhone behind regularly or need Family Setup. Otherwise, save your money and buy the GPS model. For a more detailed comparison, see The pros and cons of a cellular Apple Watch.

Can you use an Apple Watch without an iPhone?

Yes, but with important caveats. An Apple Watch can do a surprising amount without an iPhone nearby, but an iPhone is required for the initial setup and to manage some settings. You cannot set up an Apple Watch using a Mac, iPad or Android phone.

The exception is Apple Watch For Your Kids, previously called Family Setup. This allows a parent or guardian to use their iPhone to configure a cellular Apple Watch for a child or another family member who doesn’t have an iPhone of their own.

Once it has been set up, an Apple Watch can perform many tasks without its paired iPhone nearby – and some don’t require an internet connection at all. These include:

• Tracking workouts and activity: Record runs, walks and other exercises, close Activity rings and collect GPS data. The results sync with the iPhone when it reconnects.
• Monitoring health: Measure heart rate, track sleep, log medications and use other health features supported by the particular watch.
• Playing downloaded media: Listen to music, podcasts and audiobooks stored on the watch using Bluetooth headphones.
• Using Apple Pay: Make contactless payments without an iPhone or internet connection once Apple Pay has been configured.
• Using offline tools: Set alarms and timers, use the stopwatch and compass, and view photos that have been synced to the watch.

Other features require either Wi-Fi or a cellular connection when the iPhone isn’t nearby. With an internet connection, the watch can make and receive calls, send messages, check email, stream music and podcasts, use Maps and access online apps and services.

Fall Detection and Crash Detection can still recognize an incident without the iPhone, but the watch requires Wi-Fi or its own cellular connection to contact emergency services. This is an important consideration if you are buying an Apple Watch for an older relative or someone who may regularly be away from their phone.

An Apple Watch therefore cannot completely replace an iPhone, but it doesn’t need to remain beside it throughout the day. For a complete breakdown, read all the things an Apple Watch can do without an iPhone.

How we choose the best Apple Watch

Macworld’s Apple Watch recommendations draw on more than a decade of hands-on experience. Our writers have tested and reviewed every generation since the original Apple Watch, comparing each new model with both its current rivals and previous generations before deciding whether it deserves a recommendation.

Our assessment focuses on the factors that make a meaningful difference in everyday use:

• Real-world testing: We assess comfort, build quality, display visibility, performance, battery life, charging, health sensors, fitness tracking and software features. We also consider how well the watch performs during everyday activities, workouts and sleep tracking—not simply how its specifications compare on paper.
• Value and upgrade potential: A newer or more expensive Apple Watch is not automatically the best choice. We consider whether its improvements justify the price, whether owners of recent models would benefit from upgrading and whether a discounted previous-generation watch offers better value.
• Honest recommendations: We clearly identify compromises such as limited battery life, missing health sensors, a bulky design or features that most people are unlikely to use. We don’t recommend a product simply because it has the most impressive specifications.
• Advice for different buyers: There is no single Apple Watch that suits everyone. We recommend the Series 12 for most buyers, the SE 3 for those seeking the best value, and the Ultra 4 for endurance athletes and outdoor adventurers who need its longer battery life, rugged construction and specialist capabilities.

Our final recommendations therefore combine extensive testing, expert judgment, price analysis and practical buying advice. The aim is not merely to identify the Apple Watch with the longest feature list, but to help you find the model that provides the right balance of features, comfort and value for the way you will actually use it.