How eSIM has made Dual SIM the new normal
For years device manufacturers were highly reluctant to push out Dual-SIM feature that allows two independent subscriptions on a single device.
This is for different reasons, but mainly because it requires a second SIM slot. In high-end models this space is crucial to increase device's technical specs – screen size, processing power, battery life etc.
The arrival of eSIM has changed the dynamics. Since the SIM slot is still seen as mandatory for nearly all eSIM enabled devices the technical precondition for Dual-SIM is now readily available and the interest from consumers seems to increase continuously.
The possible implementations are:
DSS = Dual-SIM Standby: an early rather limited solution where user selects which of the 2 SIMs is able to make and receive calls
DSA = Dual-SIM Active: only few implementations were done with this design due to the additional transceiver for the secondary SIM card, consuming more of the phone's most critical resource - it's battery life
DSDS = Dual SIM Dual Standby: 2 active SIMs with only one transceiver; in principle this is the implementation of all eSIM supported devices
To make Dual-SIM function available to users remains, however, at the discretion of manufacturers and operators and can vary a lot depending on the regional markets.
And what will happen when the SIM slot finally disappears?
Currently eSIMs come with a lot of memory capacity that can hold 10 profiles or more. But, crucially, only a single profile can be active at a time.
To enable Dual-SIM, one possibility would be to put a second eSIM in the device. Given the existing capacity of eSIM, that would be a waste and also stand in the way of the up and coming integration of eSIM into the baseband chip as iSIM.
It is much more sensible to utilise what is already there and find a solution in which a second eSIM profile or even multiple profiles can be active at the same time and it can be expected to be addressed in the next GSMA version of SGP.22, which unfortunatly remains elusive.
For now there's still the SIM slot to fall back on and this seems unlikely to change any time soon.