If you like to swap SIM cards in one smartphone, or even put it in another phone, why not get a dual SIM and save yourself time and effort? To clarify, a dual SIM feature means that you can use two SIM cards (see what is SIM card used for) inside one phone. Whether simultaneously or not, that depends on the device and its specifications. Some devices put one SIM card in standby mode while the other is active. Others allow you to receive calls and texts to both phone numbers at the same time – ideal for combined personal and business use. With that out of the way, here’s a detailed explanation of the dual SIM feature.
Can I add a dual SIM feature?
The feature has to be designed and built into the phone in the factory. If yours isn’t, you will have to get a new smartphone. With that said, there might be a way to enable it by ordering third-party adapters. We wouldn’t recommend it, and won’t go into them.
What are dual SIM types on the market?
There are three main ones:
1. Dual SIM Single Standby
The oldest type, which only allows one SIM card to be active at any time. You will have to reboot the phone to access the other SIM card to make calls, send texts, or access the Internet.
2. Dual SIM Dual Active
Ideal implementation. Both SIM cards are active simultaneously and have separate network antennas. Although this means you can send and receive calls and texts at the same time, there are drawbacks. First of all, they’re more expensive to produce, and the retail price rises accordingly. Second of all, they use much more energy. That means you will be forced to get a more expensive smartphone with a large battery, be near a power outlet often, or purchase a power bank.
3. Dual SIM Dual Standby
A hybrid type that is widely used nowadays. Instead of two antennas, two SIM cards share one. Both SIM cards are in standby mode, and you can send or receive calls and texts on both. Also, you can select which SIM to use for mobile data. However, as soon as you, for example, answer the call, the active SIM takes over the antenna. The other SIM card will be temporarily disabled. When you end the call, both cards are active again and stay in standby until the next activity.
Do I need to insert both SIM cards?
No. Your phone will function normally even if you only insert one SIM card into the hybrid SIM slot.
Can I choose two different payment plans?
Certainly! You have complete freedom at choosing which SIM card to buy – Prepaid SIM, postpaid SIM, and pay as you go SIM cards are all compatible. It’s often recommended to choose one carrier since it will help avoid compatibility issues and potentially save you money. However, if your smartphone is unlocked, feel free to pick two different carriers. The same applies to everything that’s stored on a SIM card. For example, you can save contacts or delete contacts from SIM1 or SIM2.
How do I switch between SIM cards?
You will have to buy and unlock SIM cards separately with a PIN. If you forget the PIN, look for a PUK code. Some carriers require you to activate a SIM card, too. As an example, look at our guide to activate a Verizon SIM card. Once that is done, both SIM cards should be recognized. If they aren’t, check our guide on how to change a SIM card on Android and iOS. Also, here’s what to do if one SIM card is not working.
Is dual SIM and eSIM plus physical SIM the same thing?
Some smartphones, for example, Apple iPhones 11 and 12, use a soldered SIM card (eSIM or embedded SIM), which can’t be physically removed. However, they still allow you to use the SIM card removal tool to open the SIM card slot and insert a nano-SIM card. That is still officially considered a single SIM, even though you can use two SIM cards, one removable, and one soldered. But did you know you can also insert two nano-SIM cards, one on each side of the slot? This version of the iPhone isn’t sold everywhere, though. However, it allows you to use full-fledged dual SIM in dual standby mode, plus one embedded SIM.
What about cellular data and 5G?
For the older types of cellular data, meaning 3G and 4G, you can enable a Cellular Data Switching feature on both Android and iOS. This allows you to choose which SIM, network or carrier to use, and jump back and forth. Some limitations apply, especially around CDMA-enabled smartphones. For example, sometimes only the primary SIM can use 4G/LTE while the secondary is limited to 3G or 2G. But how does 5G fare? At the time of writing, smartphones don’t support 5G in dual SIM mode. You will most likely have to disable the secondary SIM to use 5G connectivity on the primary one.