Apple Watch Ultra 4 Sensor Supply Chain Ramps Up at TASC — September Launch on Track

Taiwan-Asia Semiconductor (TASC), Apple's exclusive supplier of optical sensor components for the Watch Ultra line, has begun large-volume production orders for the Apple Watch Ultra 4's sensor stack as of July 2026, according to DigiTimes. The supply chain ramp is the clearest signal yet that Apple's September announcement is on track.

What the Ramp Tells Us

TASC's production timeline is consistent with Apple's typical September launch cadence — components manufactured in July and August feed into final assembly for an early-October shipping date. The fact that the ramp is specifically tied to sensor components suggests the Ultra 4's headline upgrades are on the underside of the case, where the optical sensor array sits against the wrist.

Rumored Ultra 4 Upgrades

• Blood pressure monitoring: Bloomberg's Mark Gurman reports Apple has been working on wrist-based blood pressure monitoring — the Ultra 4 may be the first to ship it
• 15% thinner design: The Ultra 4 case is reportedly slimmer while maintaining the same rugged build quality
• 72+ hour battery life: A larger, more efficient battery combined with a new chip architecture
• Touch ID: Rumors persist about an under-display fingerprint sensor, though this remains unconfirmed
• Doubled sensor count: TASC's ramp suggests a significantly expanded sensor array compared to the Ultra 3

What This Means for Buyers

If you're considering the Apple Watch Ultra 3 at $640 on Amazon, the supply chain ramp confirms the Ultra 4 is roughly two months away. The Ultra 3 remains an excellent watch at its discounted price, but buyers who want blood pressure monitoring or the thinner design should wait for September. The Galaxy Watch Ultra 2 arrives sooner on August 6 if you're platform-flexible. Compare all premium smartwatches in our smartwatch guide.