Smart phones dual sim let you use two SIMs in a single phone. Most people who use dual-SIM phones find the functionality useful for mixing work and pleasure, rather than carrying separate phones for their work- and personal contracts.  

Another way you can find a dual-SIM phone is to search a site such as Amazon or eBay for 'dual-SIM phone', 'dual-SIM Samsung' or 'dual-SIM Sony' and so on. In doing so you might find a dual-SIM version of the Samsung Galaxy S4 mini or Sony Xperia Z3, for example. The Honor 6 is another phone that is available in dual-SIM format, just not officially so in the UK.

Something we've noticed when shopping for dual-SIM phones is that the manufacturer very rarely provides any information about the functionality other than it exists. It doesn't tell you how the dual-SIM functionality works in practice, nor whether both SIMs support 3G, or even what size SIM cards they accept.

In all the dual-SIM phones we've tested both SIMs are on standby at all times (known as dual-standby phones), but you can actively use only one SIM at a time. This means that either SIM can accept a phone call or text at any time, without you having to actively swap between them or reboot the phone. However, if you get a call on one number while a call is active on the other, it won't start ringing in your ear or give you the option to put the first caller on hold - the call will simply not be successful.  

If it's you who wants to make a call or send a text, Android has a standard SIM Management menu that lets you specify which SIM should be used for voice calls, video calls, messages and mobile data. You can either specify a particular SIM for each of these tasks, or leave the setting at Always ask. Dual SIM card cell phone allows you to combine work and family and friends apart, both are not affected.

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