Apple Watch Series 3 Teardown Reveals Larger Battery and Air Vent Moved Next to Diagnostic Port

iFixit has completed a teardown of the Apple Watch Series 3, which has a virtually identical form factor as previous models.

apple watch series 3 teardown ifixit
The display is unchanged from the Series 2, with one key difference being that it now functions as a multifrequency antenna for cellular. Series 3 models support LTE and UMTS, according to Apple's tech specs.

series 3 display
The battery in the 38mm model with GPS + Cellular has a capacity of 279 mAh at 3.82V, or 1.07 watt hours, which is only a slight increase of about 3.8 percent over the 38mm Series 2 model without cellular.

Apple said Series 3 models with cellular get up to 18 hours of battery life, including four hours of LTE and 14 hours of connection to an iPhone via Bluetooth. Series 2 models are also rated to last 18 hours with mixed usage.

apple watch series 3 battery
iFixit was surprised that Apple managed to increase the battery size while still leaving room for the added functionality of cellular antennas, radios, power amplifiers, the embedded SIM card, and so on in the same form factor.

The embedded SIM, outlined in red, appears to be sourced from ST Microelectronics, and it is positioned next to a Wi-Fi module from Broadcom and other RF chips that enable cellular capabilities in the watch.

series 3 rf chips
Last, we finally know what the tiny meshed hole is next to the diagnostic port: it's an air vent, since the Apple Watch Series 3's new barometric altimeter took over the vent's previous location next to the microphone.

apple watch series 3 air vent

Apple Watch Series 3's relocated air vent outlined in yellow

iFixit gave the Apple Watch Series 3 a repairability score of 6 out of a possible 10 points. Display repairs and battery replacements are both possible, albeit tricky, but replacing any of the component cables requires micro-soldering.

Related Roundup: Apple Watch 10
Buyer's Guide: Apple Watch (Caution)

Popular Stories

iPadOS 26 App Windowing

Apple Explains Why iPads Don't Just Run macOS

Friday June 13, 2025 7:46 am PDT by
iPadOS 26 allows iPads to function much more like Macs, with a new app windowing system, a swipe-down menu bar at the top of the screen, and more. However, Apple has stopped short of allowing iPads to run macOS, and it has now explained why. In an interview this week with Swiss tech journalist Rafael Zeier, Apple's software engineering chief Craig Federighi said that iPadOS 26's new Mac-like ...
iphone 16 pro models 1

17 Reasons to Wait for the iPhone 17

Thursday June 12, 2025 8:58 am PDT by
Apple's iPhone development roadmap runs several years into the future and the company is continually working with suppliers on several successive iPhone models simultaneously, which is why we often get rumored features months ahead of launch. The iPhone 17 series is no different, and we already have a good idea of what to expect from Apple's 2025 smartphone lineup. If you skipped the iPhone...
Logitech Logo Feature

Logitech Announces Two New Accessories for WWDC

Friday June 13, 2025 7:22 am PDT by
Alongside WWDC this week, Logitech announced notable new accessories for the iPad and Apple Vision Pro. The Logitech Muse is a spatially-tracked stylus developed for use with the Apple Vision Pro. Introduced during the WWDC 2025 keynote address, Muse is intended to support the next generation of spatial computing workflows enabled by visionOS 26. The device incorporates six degrees of...
iOS 26 Screens

Here Are All the iOS 26 Features That Require iPhone 15 Pro or Newer

Thursday June 12, 2025 4:53 am PDT by
With iOS 26, Apple has introduced some major changes to the iPhone experience, headlined by the new Liquid Glass redesign that's available across all compatible devices. However, several of the update's features are exclusive to iPhone 15 Pro and iPhone 16 models, since they rely on Apple Intelligence. The following features are powered by on-device large language models and machine...
CarPlay Liquid Glass Dark

Apple to Let iPhone Users Watch Videos on CarPlay Screen While Parked

Thursday June 12, 2025 6:16 am PDT by
Apple this week announced that iPhone users will soon be able to watch videos right on the CarPlay screen in supported vehicles. iPhone users will be able to wirelessly stream videos to the CarPlay screen using AirPlay, according to Apple. For safety reasons, video playback will only be available when the vehicle is parked, to prevent distracted driving. The connected iPhone will be able to...
iOS 26 on Three iPhones

Hate iOS 26's Liquid Glass Design? Here's How to Tone It Down

Wednesday June 11, 2025 4:22 pm PDT by
iOS 26 features a whole new design material that Apple calls Liquid Glass, with a focus on transparency that lets the content on your display shine through the controls. If you're not a fan of the look, or are having trouble with readability, there is a step that you can take to make things more opaque without entirely losing out on the new look. Apple has multiple Accessibility options that ...
Mac Studio Feature

Apple Begins Selling Refurbished Mac Studio With M4 Max and M3 Ultra Chips at a Discount

Thursday June 12, 2025 10:14 am PDT by
Apple today added Mac Studio models with M4 Max and M3 Ultra chips to its online certified refurbished store in the United States, Canada, Japan, Singapore, and many European countries, for the first time since they were released in March. As usual for refurbished Macs, prices are discounted by approximately 15% compared to the equivalent new models on Apple's online store. Note that Apple's ...
iOS 26 Feature

Apple Seeds Revised iOS 26 Developer Beta to Fix Battery Issue

Friday June 13, 2025 10:15 am PDT by
Apple today provided developers with a revised version of the first iOS 26 beta for testing purposes. The update is only available for the iPhone 15 and iPhone 16 models, so if you're running iOS 26 on an iPhone 14 or earlier, you won't see the revised beta. Registered developers can download the new beta software through the Settings app on each device. The revised beta addresses an...
iPhone 17 Pro Blue Feature Tighter Crop

iPhone 17 Pro Launching in Three Months With These 12 New Features

Saturday June 14, 2025 5:45 pm PDT by
The iPhone 17 Pro and iPhone 17 Pro Max are three months away, and there are plenty of rumors about the devices. Below, we recap key changes rumored for the iPhone 17 Pro models as of June 2025:Aluminum frame: iPhone 17 Pro models are rumored to have an aluminum frame, whereas the iPhone 15 Pro and iPhone 16 Pro models have a titanium frame, and the iPhone X through iPhone 14 Pro have a...

Top Rated Comments

TheBing1980 Avatar
101 months ago
I hope we see some real world battery life for the same watch when NOT on LTE. I want to get the GPS version. Since Apple tends to underestimate I'm hoping we get 24-26 hours of uses when not using LTE.
I just upgraded from a Series 0 to the LTE Series 3.

So far I am very impressed with the improved battery life.

Yesterday I was up at 7am and used the watch all day. (included a 45 min working with the heart rate monitor on) At 11pm I still had 70% battery remaining.

I had my phone with me, so I doubt I used any cellular data that day.
So my guess is that you may be able to get 24 hours with the GPS version.
Score: 3 Votes (Like | Disagree)
lincolntran Avatar
101 months ago
What kind of air flow could they possibly get through that vent when it is almost constantly occluded by a watch band?
I don’t think that’s its purpose. There’s no fan so there really isn’t any airflow at all. I’m not an electrical engineer but my guess that I think the main purpose of to just have an outlet to let the hot air out when there’re build up of pressure inside the watch housing as it’s not good to have a totally closed enclosure for any electronic device.
Score: 3 Votes (Like | Disagree)
porkrind Avatar
101 months ago
What kind of air flow could they possibly get through that vent when it is almost constantly occluded by a watch band?
They need almost zero flow. It just needs to move enough air to equalize the pressure inside and outside the watch. It's a minuscule requirement.
Score: 2 Votes (Like | Disagree)
MrXiro Avatar
101 months ago
I hope we see some real world battery life for the same watch when NOT on LTE. I want to get the GPS version. Since Apple tends to underestimate I'm hoping we get 24-26 hours of uses when not using LTE.
Score: 1 Votes (Like | Disagree)
iPhysicist Avatar
101 months ago
They need almost zero flow. It just needs to move enough air to equalize the pressure inside and outside the watch. It's a minuscule requirement.
This. Atmospheric pressure equalization.
Score: 1 Votes (Like | Disagree)
44267547 Avatar
101 months ago
It's pretty unbelievable the amount of technology that can incorporated into such a small casing that can fit in the palm your hand. And yet it's features and capabilities have something for everybody to convenience us in fitness and communication.
Score: 1 Votes (Like | Disagree)