The Apple Watch Series 9 and Apple Watch Ultra 2 have more in common than you might realize, even though they’re very different watches on the outside. While the $799 Ultra 2 is a tougher, bigger and pricier watch than the $399 Series 9, internally they’re almost the same. They share the same S9 chip that supports features like Double Tap, on-device Siri and speedy performance. 

So how do you separate the two? Price is likely your first consideration. The $799 Ultra 2 only comes in one 49mm size with a titanium case and LTE connectivity is included. 

But the $399 Series 9 is more complicated. First, you need to choose between a 41mm or 45mm size. Then, pick an aluminum or stainless steel case and whether or not you want the LTE version. Indeed, the 45mm Series 9 in stainless steel costs $749, which puts it squarely in the ballpark of the Ultra 2. 

The price factor might not be as clear-cut as you first thought. To help you make the right decision, I wore both watches for a month. Here’s what I found.

Apple Watch Ultra 2 Screen: Bigger, brighter than Series 9

The Apple Watch Ultra 2’s 49mm case is bigger than the 45mm Series 9, but the screen itself is also slightly larger. That means you can fit slightly more on the Ultra 2’s screen, helpful if you are using an app like Maps for example.

The easiest way to spot the size difference is to boost the text size to the maximum on both watches. Part of the text gets cut off on the Series 9 compared to the Ultra 2, like in the image below.

But the biggest difference in day-to-day wear is screen brightness. The Ultra 2’s screen gets brighter than the Series 9 at 3,000 nits vs. 2,000. I’ve had zero issues seeing the Series 9 indoors or outdoors, but having a little extra brightness on the Ultra 2 is nice for readability, especially for workouts in bright sunlight.

It also gives the flashlight a boost. You can turn the digital crown on the Ultra 2 to force the screen to its brightest setting when using the flashlight, which is helpful in dark situations. I went spelunking with the first Apple Watch Ultra, which shares the same screen brightness as the Series 9, and the Ultra 2. The additional brightness on the Ultra 2 really did make a difference when illuminating the rock face. 

Apple Watch Series 9 might be better for smaller wrists

There’s no ignoring that the Ultra 2 is a large watch. Coupled with the chunkier digital crown and flat display, it stands out a lot more than the Series 9. My wrist measures 152mm and even though the Ultra 2 looks hefty, it’s surprisingly comfortable on a small wrist and I wear it all the time.

But there’s no ignoring the fact that the Ultra 2 might be too large if you have an even smaller wrist than mine. That means you might gravitate toward the Series 9 just to have the option of a smaller case size. I also found the Series 9 is more comfortable to sleep with if I do want to track my time in bed. 

The Ultra 2 is, however, designed to be a tougher watch than the Series 9. Its titanium case is slightly raised to give more edge protection to the sapphire crystal display. The Series 9 display has two different coverings: Ion-X glass if you get the aluminum case, or sapphire crystal on the stainless steel case

Both are IP6X dust-resistant and water-resistant, but the Ultra 2 can go down to a depth of 100m compared to 50m. It also has an exclusive Depth app and support for the Oceanic Plus app that turns the watch into a dive computer.

Apple Watch Ultra 2 Action button speaks my love language

The Ultra 2 has another significant design feature that sets it apart from the Series 9. Just like the Action button on the iPhone 15 Pro and Pro Max, you can press it to quickly launch your favorite workout, the flashlight, the stopwatch and other preset tasks.

My favorite way to use the Action button is to trigger a Shortcut, which is a quick way of accessing a favorite feature or tasks in an app. You can program a Shortcut yourself using the app of the same name on the iPhone. 

One of my top Shortcuts is to navigate home from my current location, but you could also use it to control connected home appliances, or toggle on a focus mode. The possibilities are almost endless. I even made a Shortcut to Rickroll myself (yes, seriously). You can see that in action on the video on this page.

All is not lost on the Series 9 if you like Shortcuts. You can still set a complication on the watch face to launch a Shortcut, it just requires an extra tap on the screen to confirm you want to run it.

Both Apple Watch Ultra 2 and Series 9 have Double Tap and Siri

You can use the Double Tap gesture to control both the Apple Watch Series 9 and Ultra 2. It’s powered by the S9 chip and works exactly the same on both watches. When the screen is active, you can double tap your thumb and forefinger to complete a task, rather than touch the screen. For example, raise your wrist and double tap your thumb and forefinger to reply to a message with dictation, then double tap to send.

It’s helpful, accurate and works in many of Apple’s apps. You can answer a call, change tracks and start or stop timers. For third party apps, it will generally perform the default action when you double tap. I use it to quickly reply to Slack messages from colleagues when I’m unable to grab my phone or type a response out at my computer.

It works the same on both watches, because they run the same chip. On-device Siri is also the same, so the watches don’t have to ping the cloud when you ask Siri to do something that doesn’t require the internet. That includes tasks like starting a workout or setting a timer. They also both have 64GB of internal storage, great if you like to put music or have lots of apps on your watch.

Apple Watch Ultra 2 has some special tricks

While you’ll get the same great WatchOS 10 experience and a wide selection of apps on both watches, the Ultra 2 has additional features that swing the pendulum in its favor.

First, watch faces. You might not think this is enough to make you choose the Ultra 2 over the Series 9 but the exclusive faces are nice: Modular Ultra and Wayfinder. They fit a lot of detail on the screen and have room for seven or eight complications, respectively. And they have a dark mode that turns either watch face red when the light sensor detects it’s dark outside.

The Ultra 2 also has a three-mic array to help cut out more wind noise when on calls, plus dual speakers which get louder than the Series 9. I took both watches outside and recorded the call audio so you can hear the difference on the video on this page. 

Then there’s the matter of connectivity. The Ultra 2 has LTE as standard, whereas you need to buy the specific LTE (or cellular) version of the Series 9 if you want to use your watch without your phone nearby. Once you add a data plan from your existing wireless provider, you can leave the iPhone behind and still connect to your favorite apps, send messages or make calls from your wrist.

Both have the second-gen ultrawideband chip which means you can find your phone from the watch with precision finding, as long as you have an iPhone 15. If you have an older iPhone, ping your phone from your watch to make it ring.

Apple Watch Series 9 and Ultra 2 have very similar health tracking

Both share a temperature sensor, blood oxygen sensor, ECG or electrocardiogram app, as well as the option for high and low heart rate and irregular heart rhythm alerts. The heart rate sensor is also the same on both watches and accurate when compared to a chest strap.

Fitness tracking is identical and you keep track of your progress using the Apple Watch Activity app. You can also connect Bluetooth accessories like power meter pedals to both watches, create multisport workouts, and keep an eye on your heart rate zones.

A compass app, back track and waypoint functionality is standard on both watches, as well as car-crash detection, fall detection and emergency SOS.

The differences come down to the Ultra 2’s 86dB siren for safety and GPS. The Ultra 2 uses dual-band GPS, both L1 and L5 bands, while the Series 9 uses L1. That means the Ultra 2 is more accurate at tracking distance and route information in built-up areas specifically. But for regular outdoor use for runs in the park or tracking a bike ride on the trails, the Series 9 still does a great job.

Apple Watch Ultra 2 has the best battery life, period

The Ultra 2 knocks the Series 9 out of the park on battery life. It doesn’t matter how you use the watch, whether you’re running a marathon or just using it as a watch to tell the time and get notifications, it runs rings around the Series 9.

Apple officially rates the Series 9 at 18 hours and the Ultra 2 at 36 hours or runtime. But this is conservative, because I’ve been able to stretch both a lot longer. With what I’d call regular use  (phone notifications, the always-on display, a GPS workout and sleep tracking) you can get a day and a half from the Series 9 before charging. With the same use, I can get closer to three full days from the Ultra 2.

Both have a low power mode to extend the battery even further, but of course your mileage will vary depending on how you use the watch. Resource-intensive tasks like using LTE and listening to music over Bluetooth will deplete your battery sooner. We have more on specific battery life usage in our Apple Watch Series 9 and Ultra 2 reviews.

Both also support fast wireless charging, as long as you have an 18-watt or higher adapter. The Series 9 charges faster than the Ultra 2 from flat to full because it has a smaller capacity battery.

What’s the difference between Apple Watch Series 9 and Ultra 2?

With a similar overall feature set, including Double Tap and on-device Siri, the main differences between the Apple Watch Series 9 and Ultra 2 comes down to size, price and battery life. The Series 9 is less expensive, has a slimmer design and two size options compared to the Ultra 2. But you will need to charge it more often.

Both Apple Watches are a great pick if you want a versatile smartwatch that works with the iPhone. After wearing both for a month, the Apple Watch Ultra 2 is my favorite for two main reasons, if price wasn’t my primary consideration. Its long battery life means I no longer have battery anxiety about needing to charge it every day. And the Action button is so helpful and customizable, it makes using the watch much more enjoyable and convenient.