Wireless Service

Dual SIM: What is it? What does it mean? How does it work?

Sara Nuss
February 26, 2023

Dual SIM phones open up the opportunity to store multiple numbers on one device. This is huge. Current technology allows phones to switch seamlessly between multiple accounts. With all of these technological advancements, as well as stronger processors, battery life is more and more valuable. 

There are a couple of phones with exceptional battery life that companies have recently deployed to combat the increased energy usage of new technologies like Dual SIM phones. 

A lot of the new developments in phones also increase battery consumption. Do you remember when feature phones had batteries that lasted days and days? Well, their batteries were nothing special, but the phone just didn’t need much power to operate! You may notice that battery life extends far longer when you do not use your phone. How much battery do you want on your device? If you are someone who exists nearby a charger all day, it is easy enough to give a bit of a charge whenever it gets low, but if it starts to become a big inconvenience, that’s when it might be time to switch to a new device! That’s enough about battery life. It’s time to jump into dual SIM technology. 

Dual SIM devices offer a lot for those who operate multiple phone numbers. This article will cover the basics of dual SIM technology, focusing on these three questions: 

  • What is it? 
  • What does it mean? 
  • How does it work? 

What is it?

Dual SIM encompasses everything that allows phones to contain multiple numbers on the single device. There are a variety of reasons why you might want multiple accounts on your phone, but business and travel are the biggest two. The overarching idea behind dual SIM technology is that there is space within the phone with a combination of physical SIM slots and eSIM hardware. These slots let these numbers exist entirely separate from one another. You can have multiple plans or carriers within the phone, and the current dual SIM technology lets every number within the phone function simultaneously. 

Before there was dual SIM technology people carried multiple phones. Many still do. There are practical advantages to having separate devices for each number; many people still operate two phones to separate those numbers physically. 

That being said, carrying around two phones all the time is less than ideal. In terms of pocket space alone, two phones can be more than a bit inconvenient. The first dual-SIM phones gained popularity around the turn of the century, but, even today, not every phone has dual-SIM compatibility. By now, we’d wager that your device is capable of housing multiple SIM cards, but we recommend a quick google just to make sure. 

Types of Dual-SIM Phones

There are three types of dual-SIM phones. After googling to see if your phone has dual-SIM compatibility, it is important to see whether it is regular, standby, or active. Different kinds of devices open up different courses of action when it comes to using your dual-SIM device. Here’s how each type of dual-SIM phone operates the separate accounts: 

  • Dual-SIM phones switch between which account is active. With this kind of device, you have to manually switch between accounts, and whichever account is active will have complete control over the device. 
  • Dual-SIM Standby phones allow both accounts to be active when neither is in use, but you have to switch between the SIM card that makes texts and calls. Dual-SIM (non-standby) phones won’t show texts or incoming calls for the other SIM card and standby will. 
  • Dual-SIM Active phones are the most advanced and allow both SIM cards to function concurrently. With this phone, you can create contact groups where group one is automatically directed to SIM card one, and group two to SIM card two. With a dual-SIM active device you need to set up some processes and systems when you set up the device, but once you do, most of the SIM-switching is automated! 

Activating dual-SIM technology on your phone doesn’t change much, but you will notice a higher drain on your battery. Both SIM cards are actively searching for a network and running other normal functions, resulting in a bigger battery drain. Normally, SIM card usage has a negligible drain on the battery, but if you are in a low signal area for one of your cards it will work harder to get you a signal. You may have noticed that your phone drains more battery on standby in low signal areas, and that’s due to the SIM card working overdrive. With two SIMs, especially if they use different networks, you will notice more battery drain, but it is nothing crazy compared to other battery-intensive activities like streaming video or gaming. 

Dual-SIM Phone Users

Dual-SIM phones are meant for people who want multiple numbers on one device. Many people have dual-SIM capable phones, but until they add a second number and SIM card to the device, they function the same as any other phone. Dual-SIM phones for people with multiple numbers still do a good job of separating the work number and personal number. Only one SIM card is active at a time in the user interface, so apps like social media, pictures, and games will all go through your personal SIM (unless you want the UI set to the other number). While only one SIM card is active at a time in your user interface, you will receive text and call notifications from each number whenever it is relevant. 

With dual-SIM active phones, even if you are on a call with one number you will still receive notifications from the other SIM. The SIM you set for your UI will also use mobile data, so watch out if you have a limited-data plan on your dual-SIM device. You need to be conscious of the active SIM card in relation to data usage, but other than that both should operate at full functionality within your device. 

There are two major users of dual-SIM phones at this time, but more applications are sure to pop up as time goes on. The two major users are people who need a second line for work, and those who need it for travel. 

  • Work phones are a classic way for people to remain connected to their job at all hours of the day, and to separate their personal life from their work life. Dual-SIM phones let people do all of that on one device! People with a work number can customize their settings much more than those trying to fit it all on one device. For instance, they can all notifications on their work number on do not disturb when they are off the clock without worrying about pesky notifications popping up on their personal device. 
  • Travel phones are a popular alternative to pursuing international phone plans from US carriers. If you travel with regularity to the same country, purchasing a phone plan from that nation provides much better rates and cheaper prices than what’s offered in the United States. A dual-SIM device lets you do it all from your personal phone, and you can put your personal number on airplane mode for the duration of your stay to ensure you don’t incur any roaming charges. 
Phone users with a new device may want to consolidate their accounts rather than lug around multiple phones. Dual SIM technology opens that door. 

What does it mean? 

You might have heard about the buzz surrounding dual-SIM devices and wondered what it all meant. Dual-SIM devices provide a simple benefit to phones, but let’s talk about how that technology affects cell phones as a whole. This section will cover what it means for dual-SIM devices to grow in popularity and touch on the rising interest in eSIM devices. 

Extra Options for New Devices

Lots of new devices have eSIM compatibility as well as two physical SIM slots in their tray, opening up the possibility for a lot of customizability in plans. The eSIM technology especially lets users switch from network to network with much less hassle and port their number effortlessly from one place to the next. We may see an overall shift from physical SIM cards to eSIMs in the future, but it does not seem like companies are ready to phase out physical SIMs just yet. In time, physical SIM phone plans may become a thing of the past, just like the headphone jack or the home button on the iPhone. 

Pros and Cons of eSIM and Physical SIM

Embedded SIM cards are popular, but only time will tell about how popular they become. SIM cards will likely remain in circulation, but it is hard to look past the impressive set of benefits that come with eSIM cards in phones. Here are some pros to eSIMs: 

  • It is easier to switch networks
  • No chance for accidentally damaging your SIM card
  • You can store multiple networks on the same eSIM card
  • Embedded SIM cards are common additions to dual-SIM devices
  • Embedded SIM cards save valuable phone space

This suite of benefits comes together to create an impressive list of reasons why to switch to an eSIM card. Well, for companies to switch to eSIM cards. Most regular phone users won’t notice much of a difference between using a physical SIM card and an eSIM card. For dual-SIM users, having one of your networks on the eSIM card is nice, but if your phone comes with two SIM slots then you have even more flexibility. Here are some of our favorite dual-SIM devices: 

  • Samsung Galaxy S22 Series
  • Samsung Galaxy S21 Series
  • Google Pixel 7
  • Google Pixel 3a
  • iPhone 13
  • iPhone SE (3rd Gen)

The only major downside to using eSIM for networks is that it is harder to switch between devices. It is not super challenging, but switching devices with a physical SIM is as easy as taking it out of your old device and slotting it into the new device. 

A Decline in Physical SIM Usage

While the differences between physical SIMs and eSIMs are subtle, a lot of the control lies in the companies and phone providers. Imagine, if you will, a new line of phones marketed with the fact that they no longer have a physical SIM port and instead rely completely on eSIM. That sounds pretty cool! Wireless companies also control the overall ability to use physical SIMs. Lots of wireless companies offer physical SIM phone plans and eSIM phone plans right now. Similar to the marketing with phones, a wireless provider may market their new service as eSIM only, or otherwise incentivize eSIM phone plans. 

The bottom line is — Your phone will work fine with an eSIM phone plan or a physical SIM phone plan. 

Traveling is made easy with dual-SIM compatibility. Call in advance of your flight, secure a great plan from your destination, and activate it upon your arrival. 

How does it work? 

The majority of setup involved in dual SIM phones happens at the very beginning. Users must configure their devices to know when to use SIM one, and when to use SIM two. Of the three options, dual-SIM active phones are the most advanced and the ones we recommend for all users. These phones have been around long enough that there are older, more affordable models available for purchase if you want dual-SIM capability without dropping hundreds of dollars on a new device. Let’s run through the setup for Apple and Android devices. 

How to set up a Dual SIM Apple Phone

All of the newer models of Apple devices are dual SIM and eSIM compatible. This opens up the opportunity for you to use multiple physical SIMs or activate your eSIM for one of the lines. The input process for the physical SIM cards is simple enough, and once you activate both accounts you can work out the device defaults to ensure the right SIM card is active at all times. Apple lets you label your plans for an easy comparison, letting you choose from the following tags:

  • Business
  • Cellular Data
  • Personal 
  • Primary
  • Secondary
  • Travel

How to set up a Dual SIM Android Phone

Like Apple phones, Dual SIM-compatible Android phones have a SIM card reader that reads both SIM cards and eSIM compatibility. They also have a hybrid tray, where one of the slots can hold a micro SD card that you can insert to increase phone memory (as long as you don’t need it for a second SIM card.)

After inserting both of your SIM cards, you are able to go into the phone’s settings and activate the second card after your phone detects it automatically. From there, you can choose from a list of tags. 

Which Should You Purchase?

That’s all up to you! Both Apple and Android have some amazing options for phones, and if you are purchasing a new phone, we recommend making a list of some of your favorites from each provider and picking out the one that you will be most comfortable using. There are enough dual SIM active phone options that there are great options no matter where you are looking.

There is no telling where dual-SIM technology will lead us. We are excited to see continued advancements in the field and keep track of what’s new! 

Key Takeaways

Dual-SIM technology is an exciting way to power up your phone with multiple numbers. You can use them however you wish to best utilize your device. Before you go, here are a few key points to remember the next time you think about dual-SIM cell phones

  • There are three types of dual-SIM phones, with dual-SIM active being the most advanced
  • Mostly businesspeople and travelers take advantage of dual-SIM phones at this time
  • Dual-SIM phones are made more popular as eSIM compatibility rises in phone models and wireless providers
  • It is fairly easy to set up a dual-SIM device, and once you set it up it should run smoothly from then on

Frequently Asked Questions

What Happens When People Call Both Numbers? 

Very little. With a dual-SIM active device, you can operate both SIMs simultaneously. This lets you put one call on hold while you answer the other, or even set up a conference call with both incoming calls. 

What does a dual SIM card do? 

A dual-SIM cell phone allows for two active SIM cards in one device. This lets you carry around one device with all your information rather than keeping a separate phone for work or travel, 

Does dual SIM mean two numbers? 

Most of the time, yes. A dual-SIM phone allows for multiple active numbers, plans, or accounts. The phone functions just fine with a single number, and chances are you have a dual-SIM compatible phone right now! 

Why would I want dual SIM?

You want dual-SIM if you ever want multiple numbers on one device. Even if your phone is dual-SIM compatible there’s no need to input a second SIM card.

Sara Nuss
Sara Nuss is a journalist from Pittsburgh, PA that specializes in wireless, dewi, phone plan advice & blockchain.
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