Samsung does make dual-SIM versions of its flagship handsets but they are only made available in select markets. If you were not able to acquire an official dual-SIM Galaxy S7 or Galaxy S7 edge then fear not, there's a hardware hack that can enable you to get dual-SIM compatibility on your Galaxy S7 handset. It can even be used to run three SIMs on a dual-SIM Galaxy S7.
SIMore has introduced its ZX-Twin dual-SIM adapter for the Galaxy S7 and the Galaxy S7 edge, it's basically a strip of flat ribbon wiring that is connected to the phone's main SIM slot. It makes the connection with the main SIM tray while the dual-SIM tray exists entirely outside the device. This means that you will have to use a protective case with this hardware hack because it would be otherwise impossible to manage the external cable and SIM slot.
You will need an unlocked Galaxy S7 handset for this to work. The external SIM tray supports both nano-SIM and micro-SIM cards, it features support for all standards like 4G LTE, HSDPA, GSM and 3G WCDMA. The only caveat here is that since there's no provision in the software for dual-SIM support, you will have to restart the handset every single time you want to switch to the other SIM. The adapter costs €49.90 and will be available starting September 26.