Aside from having a normal and an XL model, it seems that Google isn’t really a fan of having two of something. It doesn’t have two main cameras nor does use the full extent of dual SIM capabilities. One of those might be changing in the upcoming Pixel 4 phone later this year and, no, it won’t be the cameras. A Googler commenting on a source code change for Android Q let it slip that the 2019 Pixel will have “dual SIM functionality”, which hopefully means the true dual SIM capabilities users expect these days.
In truth, the Pixel phones since the 2017 Pixel 2 actually have dual SIM support. Like Apple’s newest iPhone, those Pixel phones have a tray for one SIM card while the second is provided by an eSIM. Never mind the fact that eSIM support is very limited in the US and the rest of the world, the Pixel’s Dual SIM mode is one that goes back to the early 2000s.
Like those older dual SIM phones, the current Pixel use Dual SIM Single Standby or DSSS. This just means that you can’t use both SIMs at the same time, in this case the physical SIM and the eSIM networks simultaneously. You’ll have to switch between the two networks to receive calls and messages from the respective network.
What most dual SIM Android phones and the 2018 iPhones use is Dual SIM Dual Standby (DSDS). You can make and receive calls and messages on both networks without switching as long as the SIM isn’t being used for that same purpose. Ideally, phones would have Dual SIM Dual Active (DSDA) capabilities but those require two wireless radios instead of one.
The Googler seems to suggest that this year’s Pixel phones, which will run on Android Q, of course, will have DSDS dual SIM functionality. Just as interesting, however, is the note that the Pixel 3 does have that as well but is limited to internal testing. Hopefully, Google will decide to flip the switch for the Pixel 3 when it gets Android Q.