Phones have traditionally used physical cards called SIM cards to connect to cellular networks, but there has been slow progress on switching to a digital version called eSIM. One of the reasons we haven't seen more phones dropping the SIM card slot entirely is that Android doesn't have great support for multiple eSIMs, which needs to happen first before most manufacturers can make the switch. The upcoming Android 13 update appears to be laying the groundwork for exactly that.

Esper reports that the codebase for Android 13 contains an implementation of a patent filed by Google in 2020, which allows multiple SIM profiles to be used on a single embedded chip. This works by splitting the single physical data bus between the modem and eSIM chip into multiple logical interfaces that are multiplexed on a single physical interface. It's sort of like how most modern CPUs split physical CPU cores into logical CPU cores, so more tasks can be performed at the same time.

Unlike physical SIM cards, which require a large slot on the side of a phone or tablet, eSIM only requires a small component on the device's motherboard. That leaves more space in the phone for a larger battery, camera hardware, or anything else. However, there haven't been many phones that drop the physical SIM card slot entirely — partially because many carriers still don't support eSIM, and partially because many devices sold internationally need to have two SIMs of some kind. Two eSIMs is an option, which the iPhone 13 series offers, but that adds more complexity.

Google hasn't mentioned this functionality publicly yet, but if it does stay in Android 13 for the final release, we'll likely hear more about it soon. The new functionality could lead to wider eSIM support across phones, as long as carriers can be convinced.

Source: Esper