Dual SIM phones come with a variety of benefits, making them a must-have for many people. However, not everyone understands what dual SIM means or how dual SIM phones work.
We're here to explain everything you need to know about dual SIM phones, their benefits, and how eSIMs fit into this picture.
What Is a Dual SIM Phone?
Dual SIM phones support the insertion and use of two SIM cards on a single device. This differs from a single SIM device, which only has a slot for one SIM card. Of course, you'll need an unlocked phone to take advantage of the dual SIM feature if it's supported. And that's one of the top reasons to buy an unlocked phone.
The majority of dual SIM phones have active dual SIM functionality. A dual SIM phone can support two active SIMs at the same time, without requiring you to remove and swap SIMs to change phone number.
This means you can receive calls and texts from both lines. You can also usually adjust which SIM is your primary data or voice call card. Some dual SIM phones even support the ability to hold a single conversation with two callers on two different lines.
Meanwhile, the other type of dual SIM phone is a standby dual SIM device. Standby dual SIM devices require you to switch between SIMs in your device settings to activate them. Your phone only connects to one network at a time, so you won't receive texts or calls for both at the same time.
There are also dual SIM smartphones that support the addition of either a second SIM or a microSD card---not both. This is a limited type of dual SIM functionality seen on older smartphones that means you have to choose between a second SIM or extra storage.
What Is an eSIM?
A more recent type of dual SIM phone is one that supports an eSIM. An eSIM, or embedded SIM, is a built-in microchip that acts as an electronic (rather than physical) SIM card. Since it enables remote SIM provisioning, an eSIM does not need to be swapped out when changing carriers. Rather, these embedded SIMs use software to load profiles and mobile plans from your mobile operator.
While eSIMs can completely replace the physical SIM card in a device, they are also used in dual SIM devices. For example, the iPhone XS, iPhone XS Max, and iPhone XR smartphones feature a dual SIM setup with a nano-SIM and an eSIM.
However, due to the inconsistent adoption of eSIM technology by manufacturers and mobile carriers this setup is not widespread yet. Most dual SIM devices still use two physical SIM cards. It is likely that more dual SIM devices featuring an eSIM will appear in the future as the technology spreads.
You can find out more about how to use and set up an eSIM in our guide on the topic.
Dual SIM vs Single SIM: The Benefits of Dual SIM Phones
There are a variety of benefits to having a dual SIM versus a single SIM phone. In fact, many consumers rank dual SIM support as an essential feature for their smartphones.
Here are some of the benefits of dual SIM phones over phones that only support one SIM card...
Two Numbers on One Phone
Dual SIM phones allow you to use two different phone numbers on a single device. This is useful for people who may have a personal and work number, but don't want to use two different devices.
Getting the Best Carrier Deals for Data and Calls
A dual SIM phone lets you take advantage of the best deals when it comes to carriers. Often you will find that one carrier has great data rates, while another has better voice call or overall bundle deals.
Using a dual SIM device lets you take advantage of both deals. You can use one SIM for your data bundle, and another for other bundles.
Since dual SIM phone settings allow you to set your primary call and primary data SIMs, it's incredibly easy to use this approach.
Keeping Your Old Number Without Needing to Port
If you don't want to go through the hassle or cost of porting your old number to a new carrier SIM, you can always use a dual SIM device. Depending on your contract terms, your old carrier will usually convert the old SIM to a prepaid SIM. You can then add a second SIM to your device from a new carrier.
While porting your number is relatively easy, this also depends on how efficiently your carrier handles customer service. Some people don't want to go through the transition period involved in porting a number.
With a dual SIM device, you can still receive calls and texts to your old SIM, and don't have to worry about porting your number.
Stay Connected During Carrier Outages
Another lesser-known benefit of dual SIM phones is the ability to stay connected during carrier outages or coverage gaps. Carrier coverage can differ in certain areas, with some having better connectivity in certain zones. With a dual SIM phone, you can try to switch to your other SIM to see if you get better connectivity.
This also works when it comes to carrier-specific outages. If one carrier is experiencing technical difficulties, you can switch to your other SIM in the meantime.
Dual SIM Phones: Which Brands Make Them?
Dual SIM smartphones are more prevalent than ever, so they are no longer really limited to specific devices or brands. Most devices released since 2018 have dual SIM support.
However, smartphone companies with major stakes in China and developing markets tend to include dual SIM functionality more often. Their track record of dual SIM support is also longer, meaning that many devices released before 2018 from these brands will still have dual SIM slots.
Nevertheless, major American brands such as Apple and Google now also include dual SIM functionality in the newer iPhone and Pixel devices.
Other brands that frequently make dual SIM smartphones include Samsung, Huawei, Xiaomi, Sony, LG, and OnePlus. If you are interested in a dual SIM smartphone, check the specifications of a smartphone you are considering buying. This will let you know whether it supports dual SIM functionality.
How to Manage Your SIM Card
If you're still hesitant about the technicalities of dual SIM phones, or want to find out more about your single SIM cards, there are tools to help you.
Managing your SIM cards isn't as daunting as it seems. In fact, SIM cards actually have quite a bit of data and useful information you can use.
If you want to find out more about your own SIM, check out our guide on Android apps to manage your SIM cards.