Apple Watch Series 12 and Ultra 4 appear to contain 128GB of NAND flash storage despite being sold with only 64GB of accessible capacity, according to new hardware findings.
If accurate, that means buyers are sitting on an extra 64GB of storage that Apple has deliberately kept locked away from them.
Why Apple might limit how much storage Apple Watch owners can actually use remains unclear.
One possibility is that the reserved capacity serves as a write-endurance buffer, a common technique with NAND flash where manufacturers set aside a portion of storage to absorb the wear from frequent read and write cycles, extending the lifespan of the chip over time.
Another is that Apple is reserving space specifically for the continuous sensor data the watches generate, keeping that workload separate from user-accessible storage.
For most Apple Watch owners, 64GB is already more than enough to store music, podcasts, and apps locally on the device.
The practical consequence of the remaining capacity being locked is minimal in day-to-day use.
The more pointed question is whether withholding that storage could affect long-term software support or limit the scope of future features, including anything Apple Intelligence-related that might eventually come to watchOS.
Both devices launched following Apple’s September 9 “Surprise and Shine” event. Independent teardowns, which typically follow a device launch by days or weeks, should clarify whether the 128GB figure holds up under direct physical examination of the hardware.
