One of the more under-appreciated features of the Pixel 5 and Pixel 4a 5G is support for Dual SIM Dual Standby (DSDS). The feature allow users to use two SIMs (one physical and one eSIM) to make calls and texts through one carrier and use data-only on the other. Unfortunately, the devices are limited to 4G networks when both SIMs are enabled, but that is apparently about to change.

Google’s own support page explains that the Pixel 4a 5G and Pixel 5 only support 4G connectivity when both SIMs are provisioned.

Important: Pixel 5 and Pixel 4a (5G) phones with two SIMs in use will fall back to 4G networks. To connect to 5G networks, temporarily turn off the SIM that isn't set to use data.

However, a code change posted to the Android Open Source Project (AOSP) suggests Google is configuring both devices to support DSDS and 5G networks. AOSP is open source and allows contributions from all developers, but the change came from Google’s own team and has been merged.

The commit description specifically refers to changing the device configuration for “Bramble,” which is the codename for the Pixel 4a 5G. However, the code that's being changed is under the device tree for “Redbull,” which is the codename for the shared device tree for the Pixel 5 (codename “Redfin") and Pixel 4a 5G. So, it’s likely both devices will support DSDS and 5G networks whenever the change ends up in a public build.

This commit was just merged, so we don't know when exactly this will be enabled on the Pixel 5 and Pixel 4a 5G. But it could happen when Google rolls out a security update in December.

Google Pixel 4a 5G Forums ||| Google Pixel 5 Forums

DSDS capabilities have been supported by Google devices since the Pixel 3a. But supporting DSDS and 5G networks simultaneously would be new territory for the company.

Thanks to XDA Recognized Developer luca020400 for the tip!

Update 1: 5G DSDS support in March 2021 Pixel Feature Drop

On Monday, Google rolled out an update to its supported Pixel phones bringing the March 2021 security patch level and the latest Pixel Feature Drop. What they didn't tell anyone was the fact that the update also enables dual SIM, dual standby (DSDS) when one of the provisioned SIMs is connected to a 5G network (H/T Reddit user rinsf). This means you can finally connect to a 5G network using one SIM without having to disable the other SIM. We've been waiting for this change to happen when we spotted a commit for the feature back in October, and it's finally here in the latest update.