iPhone XS models and newer feature both a physical SIM slot and a digital eSIM, allowing for a feature known as dual SIM, dual standby. This means you can have two lines of service on one iPhone, which is useful for purchasing data-only plans while traveling abroad or having personal and business lines on a single iPhone.

5G will not be available in Dual SIM mode on the iPhone 12 and iPhone 12 Pro at launch, however, according to an internal training document for Apple employees shared on Reddit. MacRumors can confirm that the document is authentic.

From the document: "Does 5G work with Dual SIM?"

When using two lines in Dual SIM mode, 5G data isn't supported on either line and will fall back to 4G LTE. If customers are using eSIM only and are on a 5G supported carrier and service plan, they'll have 5G access.

According to an internal Verizon slide obtained by MacRumors, however, Apple plans to enable 5G support in Dual SIM mode with a software update later this year. In the meantime, Verizon says that eSIM customers must remove the physical SIM from their iPhone 12 or iPhone 12 Pro to access its 5G network.

5G is automatically enabled on iPhone 12 and iPhone 12 Pro models, as long as users have chosen a supported wireless carrier that offers a 5G network. To access 5G while roaming in other countries, Apple's document says that customers can purchase a local SIM card or eSIM plan and use it as a single line with 5G where available.

iPhone 12 and iPhone 12 Pro pre-orders began last Friday, and shipments will begin arriving to customers this coming Friday. iPhone 12 mini and iPhone 12 Pro Max will be available to pre-order starting Friday, November 6.

Source: Macrumors