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3 min read 19 comments

What are dual-SIM phones and how do they work?

You may have heard of, or are interested in, using smartphones that employ dual-SIM cards but aren’t exactly sure how it all works. Is it more expensive? Does one need to change mobile carrier? Which smartphone should I buy? Find out what dual-SIM phones are and how they work right here.

xiaomi mi4i dual simcard
What are dual-SIM phones and how do they work? / © ANDROIDPIT

How does it work?

First of all, be aware that all smartphones equipped with two SIM card slots come with a SIM manager. This allows the smartphone to manage its dual-SIM capability. For example, you can decide which SIM you want to mainly use, as well as manage their data usages separately.

Depending on the manufacturer, there are options allowing one to associate a function to a SIM card by default, like which one handles outgoing calls or connects with 3G or 4G, for example.

Also, many messaging apps also support dual SIM: you can choose which SIM card you would like to use to send a message. The developers of Go SMS Pro, for example, have added dual-SIM support to their application.

Is there a special rate?

No! It’s simple, two SIM cards means two different rates. You can choose to have a SIM card designed for calls or even long-distance calls and the other for data usage for surfing the internet.

Many users go for traditional rates, coupled with rates that offer better prices when travelling abroad, for example.

Do I need a special smartphone?

You simply need a special smartphone that has two SIM card slots, which will look and act exactly the same on all dual-SIM devices.

wiko stairway dual sim
A phone with dual-SIM slots / © ANDROIDPIT

Some of the best dual-SIM smartphones are the Alcatel One Touch Idol X, Lenovo P780, Samsung Galaxy S4 Duos, Galaxy Grand 2 Duos, HTC Desire 601 dual SIM, LG G Pro Lite, Galaxy S4 mini Duos and Sony Xperia C.

What happens when I get calls on both SIMs at the same time?

Let’s say that you are communicating using SIM 1 and someone will call you on SIM 2, the latter will immediately get your voicemail. Dual-SIM devices mostly allow communication on one single line at a time.

Can I use two SIM cards from two different operators?

It depends! When a smartphone is blocked by a carrier, it doesn’t accept a SIM card that comes from another provider.

Do you have any other questions regarding dual SIM capability?



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  • I have a Samsung j5 with 2 sim cards. I can get whatsapp messages to sim card 1 but not to sim card 2. How do I overcome this problem please?

  • I am coming from Israel to the UK for two years. I purchased a new unlocked GINI smartphone (part of the pelephone mobile company in Israel) with dual sim card capacity and I am hoping that I will be able to use the phone for both my Israeli number as well as a British mobile number which I will purchase. The phone has a simple click ability to switch between the two sim cards but you can only use one at any one time -.

  • if im only using 1 sim only, do my inbox message display the sim1/sim2 only?
    when will appear or display the sim1 and sim2 on my message/text inbox?

  • So basically it's a single SIM phone with connectable (via manager) tray for a second SIM?

  • what type of sim cards do they use? like micro or nano?

  • Im using a samsung galaxy s5 but im not receiving calls one sim while connected on internet on another sim. What can i do?

  • Hi Brad,
    The latest dual SIM android devices allow you to receive calls in any of the SIM cards without switching anything in the phone. You will only need to set up which SIM card will be used for 2G or 3G when inserting a new SIM card, onwards the phone should automatically pick up the calls based on the initial configuration, which will remain until you change any of the SIM cards again.

  • Hi all
    a dual sim question
    .same or different network providers is prob not an issue for me but say for example. ..
    im on a call on sim 1 ,after a few minutes the call is ended , I put the phone down without making any adjustments to the phone
    can someone else call me on sim 2 .
    again not having to switch anything on the phone
    many thanks for your help

  • There are a lot of dual SIM models in the market and a many manufacturer too. There are also two main types of dual SIM devices (dual SIM active / dual SIM standby). If you want to use two different SIM cards from different telecom carriers you have to buy an unlocked handset, but you can also buy an unlocking code or root your phone and get total control of your phone. In summary, there are many things that you can do with a dual SIM phone, to get more ideas you can visit: http://www.dualsimandroidphones.com

  • Here in New Zealand there are 4 carriers. Only two do GSM as a backup of 3G and one of those Vodafone GSM coverage is bad, 3G good. Telecom NZ and Skinny Mobile only do WCDMA so dual WCDMA SIMs is a must..

  • To be honest I like that one of sim's is 2g for the battery management. 2 3g at once could be a killer for it.

  • The one problem I've seen with dual SIM fones is that SIM 1 does WCDMA but SIM 2 only does GSM. I see that the new Moto G has two 3G SIM slots so here's hoping it works..

  • Crysis, you can get call from one SIM with data coming from another SIM, I use Samsung galaxy grand duos, ...

  • Crysis, yes you will receive the call if you're using the Internet on one of the sims. Internet connection isn't counted as a phone connection. Is exactly the same thing when you are using data connection on a single sim phone and people can still call you.
    Btw I'm a proud owner of a dual sim bought from China, a Jiayu G5 Advanced - 2gb ram and 32gb internal memory and all I can say is that I love it. I don't feel sorry for the approx 400$ payed for it including shipment and customs tax.

  • Crysis Jan 21, 2014 Link to comment

    I have a small doubt on these dual sim phones using android. Let's say i'm using a active data connection on sim1, in this case other sim is active or inactive. i.e do i get a call on the second sim while using a data connection on sim1

  • but there are many smartphone available in market that uses two different SIMs of two different operator and at the same time both still active.

    • Jep, you are right. I am glad Not to live in the USA, here in germany there are tons of offers without branding, simlocks, and without contracts. I would actually never buy a Phone on contract/with simlock.

      • And almost forgot: on a Phone without simlock, you can User sims of different providers. If you root your phone and delete the lock, you can use sims of diffetent Providers, too.