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What is a Dual-SIM Phone?



A dual SIM phone is a mobile phone which holds two SIM Cards. Meaning you can have one card for business/local SIM when traveling to other countries and the other for pleasure. 


The first dual SIM phones required you to switch between the SIMs then turning one on and the other off. But now technology has advanced and both SIMS can be active at the same time. These types of phones are called “Active Dual-SIM Phones” but companies such as Samsung refer it to as “always on”.




                              Many phones look like this under the battery, but some have slots at the side.



I hear many people ask: What are they good for? Are they even useful? And also ‘I have never even seen one in my life’.


I will be answering these questions in my blog so carry on reading…


How does it work?

Dual SIM phones work by having two transceivers built in - they may not necessarily be one for each SIM. One could only support 3G, and the other 2G but both SIMs still can use the 3G transceiver. Where phones do have separate transceivers for each SIM, you hear people complain of how the network locks one of the SIM slots. But this is very rare.  This is called “active Dual SIM phones”.


There is a new generation of Dual SIM phones called “Dual SIM Dual Standby” (DSDS) where both SIMs are able to use the same transceiver simultaneously. So if you were on the phone, the other SIM could still receive a text. You are not able to do this on “active Dual-SIM phones”.


Many companies, to compensate battery life, give a second battery or an extra capacity battery. A dual SIM phone with only one SIM in would last 476 hours standby time, but with two SIMS in that would jump down to 322 hours (example).


Phones with dual-SIM

Dual-SIM phones have been around for years, with the first known one launched on the market in 2000 by Benefon in Finland. Since then they have been most popular in developing countries most popular in China and India. Many of the phones were lower-end devices that were very affordable, but now in the past two years it has started to change. Samsung, Nokia and HTC have all jumped into the game as they have noticed there is a market emerging for dual-SIM phones.


The Samsung Galaxy Grand DUOS (shown below) is a large 5inch touchscreen phone with mid-range specs. It comes loaded Android 4.1.2 which is run by a dual-core 1.2GHz processor along with 1GB RAM. There is also an 8 megapixel camera and a slot of a micro-SD card.


Nokia make the best but cheapest dual-SIM phones with one of the biggest dual-SIM ranges in Europe. Acer and Alcatel also make mid-range dual-SIM phones.


What are they good for?

There is actually a good list of things what a dual-SIM phone is useful for. For one it saves you having to carry two phones. For example, the same handset can be used for personal and business use. But one thing worth noting when it is this case, make sure you know which SIM someone is calling from. As you don’t want to answer the boss at a drunk party.


It is also good for travellers; if you travel you know that the bills will soon empty your wallet, especially if you’re going outside Europe. Well with a dual-SIM phone you can stick a local SIM in so data and making calls will be cheaper but also your normal SIM will still be available for calls and texts from home.


Using multiple SIM cards also allows the user to take advantage of different pricing planes for certain features on different networks. That’s why many phone manufactures don’t make many as their close ties with the mobile phone networks prefer if they didn’t as they would want customers to use one network exclusively.


You can even get triple-SIM phones.


This is LG's triple sim phone but as you can see, the phone isn't to the highest spesifications and I don't think                                                                               they will start to be will be very soon. 


What do you think? Would you ever use one? Would you like to see giffgaff have one with their upcoming handsets?


Yeah. I think that it would be a good idea to make dual sim phones
I can not see me using one , but i can identify and understand why people might be tempted. But i dont think it would be worth giffgaff stocking any just yet Smiley Happy Nice post cheers
They should be more widely available as it is a useful feature. The problem in the UK is that the choice of dual SIM handsets is very limited.
mad scientist
I'm no techno freak , but it's bad enough with 1 sim , don't think I could handle a phone with 2 sims 🇬🇧lol
Good post and well written - thank you. Could you perhaps add a further section: I was considering turning my iPhone into a dual SIM by using an adapter that you hide in your case, but don't know whether it would be worth it or whether there would be any issues? Thanks Smiley Happy

I actually wouldn't mind a dual-sim phone. I like to prepare for eventualities. In this case, if the O2 network (and therefore giffgaff) goes down, I can use another sim (e.g. 3) to still make calls and texts in an emergency. Smiley Happy

P.S. Great post, thanks! Smiley Happy


Good article, nice to know a bit more.

top cat

The last 3 phones we've bought have all been dual sim:


Star 9770

Samsung E1202

Lenovo A820


So yes there is demand for them.......certainly in my house there is!! Smiley Very Happy

Good post and really well written Smiley Happy


I have been using a dual sim phone since July and I love it. I can turn off my work's sim [on Vodafone] in the evening and at weekends and use my lovely Giff Gaff sim for me.  Think they are a fab invention, but you can only seem to buy them on the internet as current mobile phone shops don't sell them Smiley Sad


the other advantage, as mentioned above, is that with two different sims on two different networks, you will normally have a signal most of the time. Result !!!


I dont think I will use one Ill just stick witg giffgaff because whats the point havin two sims and spending money for  NEW PHONE