It is now possible for you to add a second number to your Pixel 3a device using eSim. The dual SIM support came soon after all the Pixel devices got Android 10.
Using Dual Sim, you can use one number for business and the other for home. Or you can use one for a data plan and the other for voice one. Google tells us that the Pixel Phone Help page, DSDS, and eSIM only work with some mobile carriers currently.
Another thing to note is that if you have bought your Pixel 3a from Japan, you won’t be able to use dual SIM.
To know more whether your carrier supports eSIM or not, you can contact your respective one. Once you’ve added eSIM to your phone, you can change SIM preferences by heading to Settings > Network & Internet > Mobile network > your network.
Keep following us for more updates.