Spec sheets show Apple's C2 modem is used in iPhone Duo and 18 Pro worldwide, and in iPhone 18 Pro Max everywhere except the US, where it likely uses Qualcomm

Your iPhone 18 Pro Max bought in the U.S. may have different cellular performance than models sold elsewhere.

Apple has updated its technical specifications to indicate that the iPhone 18 Pro and iPhone Duo models worldwide are equipped with its new C2 cellular modem. However, the iPhone 18 Pro Max uses the C2 modem in all markets except the United States. In the U.S., the iPhone 18 Pro Max is instead utilizing a Qualcomm modem, as suggested by code within iOS 27. Apple has not provided an official explanation for this discrepancy. This development comes as Apple continues its phased transition away from Qualcomm modems, having debuted its C1 and C1X modems in previous iPhone models. The C2 modem is reported to offer faster uploads and improved energy efficiency over its predecessors, and it supports ultra-fast mmWave 5G, a capability previously supported by Qualcomm modems in iPhones since the iPhone 12.

This modem split indicates Apple is either fulfilling a minimum supply agreement with Qualcomm or strategically using Qualcomm modems in the U.S. for specific capabilities like mmWave 5G, which Apple's C2 modem also supports. It suggests that while Apple is pushing its in-house modem technology, the transition is not yet complete and may involve regional variations based on existing supply deals or performance parity. As Apple's own C2 modem aims to surpass previous generations in speed and efficiency, the inclusion of Qualcomm in the U.S. iPhone 18 Pro Max opens the door for real-world performance comparisons. Observers will be keen to see if the Qualcomm modem can match or exceed the C2's claimed benefits, especially concerning 5G speeds and battery consumption, which could influence future modem sourcing decisions and consumer expectations.