Chipworks has done an impressive amount of investigative work on the Apple Watch and has managed to determine that the device appears to incorporate a BCM4334 Wi-Fi chip from Broadcom.
Chipworks spotted the chip in the video introduction of the Apple Watch, which shows Apple's custom designed S1 Apple Watch chip in separate layers. Based on screenshots from the video, Chipworks determined that one of the chips towards the top of the processor resembled a Wi-Fi chip. The pattern specifically matched up with the Broadcom BCM4334.
What really caught my eye is the part located in the centre at the top. The pattern of contacts beneath it shows that it is a wafer-scale package flip-bonded directly to the board. To me, that pattern looks like a WiFi chip layout. [...]
So we then compared the pattern on the board to the most likely Broadcom WiFi chips. The pattern of contacts matches a BCM4334 single-chip dual-band combo device.
The Broadcom BCM4334 is a single-chip dual-band combo that combines 802.11 a/b/g/n with Bluetooth 4.0 and an integrated FM radio receiver. It's been used in the iPhone and iPad, and in Samsung devices in the past, and it's designed for minimal power consumption in a compact size.
Though the Apple Watch appears to contain its own dedicated Wi-Fi chip, Apple indicates that it will not be able to connect to Wi-Fi on its own. The Apple Watch will instead rely on the iPhone's Wi-Fi connection, perhaps using its internal Wi-Fi for communicating with a paired iPhone under certain circumstances.
It is impressive that Chipworks was able to determine a part from the Apple Watch just from a video, especially because the device is still months away from shipping to consumers. According to Apple, the watch will be released in early 2015, with prices beginning at $349.