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 (Neutral)

Popular Stories

iphone 16 display

iPhone 17's Scratch Resistant Anti-Reflective Display Coating Canceled

Monday April 28, 2025 12:48 pm PDT by
Apple may have canceled the super scratch resistant anti-reflective display coating that it planned to use for the iPhone 17 Pro models, according to a source with reliable information that spoke to MacRumors. Last spring, Weibo leaker Instant Digital suggested Apple was working on a new anti-reflective display layer that was more scratch resistant than the Ceramic Shield. We haven't heard...
iPhone 17 Air Pastel Feature

iPhone 17 Reaches Key Milestone Ahead of Mass Production

Monday April 28, 2025 8:44 am PDT by
Apple has completed Engineering Validation Testing (EVT) for at least one iPhone 17 model, according to a paywalled preview of an upcoming DigiTimes report. iPhone 17 Air mockup based on rumored design The EVT stage involves Apple testing iPhone 17 prototypes to ensure the hardware works as expected. There are still DVT (Design Validation Test) and PVT (Production Validation Test) stages to...
iphone 17 air iphone 16 pro

iPhone 17 Air USB-C Port May Have This Unusual Design Quirk

Wednesday April 30, 2025 3:59 am PDT by
Apple is preparing to launch a dramatically thinner iPhone this September, and if recent leaks are anything to go by, the so-called iPhone 17 Air could boast one of the most radical design shifts in recent years. iPhone 17 Air dummy model alongside iPhone 16 Pro (credit: AppleTrack) At just 5.5mm thick (excluding a slightly raised camera bump), the 6.6-inch iPhone 17 Air is expected to become ...
Beyond iPhone 13 Better Blue

20th Anniversary iPhone Likely to Be Made in China Due to 'Extraordinarily Complex' Design

Monday April 28, 2025 4:29 am PDT by
Apple will likely manufacture its 20th anniversary iPhone models in China, despite broader efforts to shift production to India, according to Bloomberg's Mark Gurman. In 2027, Apple is planning a "major shake-up" for the iPhone lineup to mark two decades since the original model launched. Gurman's previous reporting indicates the company will introduce a foldable iPhone alongside a "bold"...
apple watch ultra yellow

What's Next for the Apple Watch Ultra 3 and Apple Watch SE 3

Friday April 25, 2025 2:44 pm PDT by
This week marks the 10th anniversary of the Apple Watch, which launched on April 24, 2015. Yesterday, we recapped features rumored for the Apple Watch Series 11, but since 2015, the Apple Watch has also branched out into the Apple Watch Ultra and the Apple Watch SE, so we thought we'd take a look at what's next for those product lines, too. 2025 Apple Watch Ultra 3 Apple didn't update the...
AirPods Pro 3 Mock Feature

AirPods Pro 3 Just Months Away – Here's What We Know

Tuesday April 29, 2025 1:30 am PDT by
Despite being more than two years old, Apple's AirPods Pro 2 still dominate the premium wireless‑earbud space, thanks to a potent mix of top‑tier audio, class‑leading noise cancellation, and Apple's habit of delivering major new features through software updates. With AirPods Pro 3 widely expected to arrive in 2025, prospective buyers now face a familiar dilemma: snap up the proven...
iPhone 17 Pro Blue Feature Tighter Crop

iPhone 17 Pro Launching Later This Year With These 13 New Features

Wednesday April 23, 2025 8:31 am PDT by
While the iPhone 17 Pro and iPhone 17 Pro Max are not expected to launch until September, there are already plenty of rumors about the devices. Below, we recap key changes rumored for the iPhone 17 Pro models as of April 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 ...
iPhone 17 Pro on Desk Feature

All iPhone 17 Models Again Rumored to Feature 12GB of RAM

Tuesday April 29, 2025 3:36 am PDT by
All upcoming iPhone 17 models will come equipped with 12GB of RAM to support Apple Intelligence, according to the Weibo-based leaker Digital Chat Station. The claim from the Chinese leaker, who has sources within Apple's supply chain, comes a few days after industry analyst Ming-Chi Kuo said that the iPhone 17 Air, iPhone 17 Pro, and iPhone 17 Pro Max will all be equipped with 12GB of RAM. ...

Top Rated Comments

TheBing1980 Avatar
99 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
99 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
99 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
99 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
99 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
99 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)