Google Pixel 3A Dual SIM vs Wi-Fi calling

[JohnQ86]

Is a Google Pixel 3A able the fallback the standby SIM on WiFi calling when switching from a SIM to the other on dual SIM mode? I know newer iPhone could do this but I can’t find any comments about this feature on Pixel 3A. As an Dual Standby phone, only one SIM of the Pixel could be active and the other is put on standby. Is the Wi-Fi calling will keep the other SIM “active”? Also, without any Wi-Fi available, is the Wi-Fi calling for a SIM could use data plan of the other SIM to route call and SMS?

Thanks

[Syaoran · Accepted solution]

The simplest solution in my opinion, would be to use Google Voice for a second number.  Dual-SIM devices that are dual-standby, essentially disable the other SIM while one is in use.  I don't actually have a 3A dual-SIM, but I have had other dual-SIM devices, such as the Xiaomi Mi MIX 3 and OnePlus 7 Pro.  I can tell you using dual-SIM on the 7 Pro with WiFi Calling enabled, still disables the other SIM when on a call, so no calls, texts, or data is usable on the SIM that isn't in use when the other SIM is on a call.  

[BillTelusCust]

As the original poster stated, the iPhones go to wifi calling (using cellular data if needed) on the second line when you have a call on the first one.  I am told that some google phones allow you to switch a second line to wifi calling always so that you can travel and not incur the daily roam charge on both...

[Enriqu1e]

Pixel 3A users will be able to select default networks for sending texts, making calls, and using data.