How to switch between SIMs on Xiaomi Android

Modern smartphones Xiaomi, Redmi and POCO They are almost always equipped with two slots for SIM-But owners often face confusion about how to manage these connections so that calls don't go missing and the Internet works at maximum speed exactly where it's needed. Basic configuration occurs immediately after installation of cards, but in the process of operation there is often a need to change priorities or temporarily disable one of the communication lines.

The MIUI shell interface, or the new HyperOS, offers flexible mobile management tools that go far beyond just turning on and off. You can assign one SIM to default voice calls, and leave the other one solely for receiving SMS from banks or instant messengers. Understanding these mechanisms can significantly save battery life and avoid unnecessary costs for roaming or paid services.

In this article, we will take a closer look at all the available ways to switch between SIM cards, including hidden features and automatic scripts. We will look not only at the standard settings menu, but also at the nuances of working in various situations, for example, during a conversation or when using a mobile hotspot. The correct configuration will ensure a stable signal and comfortable use of the device in all conditions.

Basic settings SIM-card

The initial setup of the dual SIM card is done through the main menu of system settings. To access these parameters, you need to go to the Settings section, and then select the item. SIM-And that's where all the key controls are, which is where you can determine which card is going to be responsible for voice and which is going to be responsible for data.

At the top of the screen, you'll see a list of installed cards with their names, which by default can be designated as "SIM 1" and "SIM 2" or carrier names. Clicking on the name of a particular SIM, you can open an extended menu where you can rename the card, change its color to distinguish visually and set a pin code. Rename is the first step to convenience, because you can immediately see in the status bar, which operator is currently active.

Below the card list are the default card selection points. The system suggests assigning a primary SIM for calls and a separate SIM for mobile Internet. If you choose the Always Ask option for calls, each time you dial the phone will ask you to choose which card to call from, which is convenient if you often call different contacts from different numbers, but can be annoying if you need quick calls.

It is important to note that the changes take effect instantly, without the need to restart the device. However, if you change the physical location of the cards in the tray, it may take a few seconds for the system to recognize new parameters. In some cases, especially after a firmware update, it is recommended to perform a complete reset of the network settings to eliminate possible software conflicts.

Internet and data management

One of the most important features for many users is the ability to quickly switch mobile internet between SIM cards. Unlike voice calls, data transfer is usually only active on one card at a time, although modern technology allows for channel aggregation, but this requires support from the operator.

The fastest way to change the source of the Internet is to use the notification bar. Swipe down from the top edge of the screen to open the control center, and find the mobile network icon (usually it displays the operator name or 4G/5G designation). Pressing this icon will open a small pop-up window where you can instantly switch to another SIM, which is especially true when the main operator loses a signal or runs out of traffic.

The mobile network settings also include a Traffic Limit feature that can be configured separately for each SIM card, which allows you to control gigabyte consumption and avoid unexpected charges. If you use one card only for the Internet, it makes sense to set a limit so that the system warns you that you are approaching the limit.

⚠️ Note: When switching the mobile Internet to a second SIM card, the connection may be temporarily severed, which will interrupt file downloads or video streaming.

Also worth mentioning is the “Game Acceleration” feature, which is often built into Xiaomi’s game modes, which allows you to temporarily redirect all traffic to the SIM card with the best signal, providing minimal ping in online games.

Switching SIMs during the call and in contacts

Two-number scenarios often require flexibility when making a call. Even if you have a default card for calls, MIUI-based Android makes it easy to change that decision for a particular contact or last dial, eliminating the need to constantly change global settings.

When you dial a number through a standard phone application, you'll always see two buttons with the names of the SIM cards under the call button. When you click on the one you want, you'll make a call from that number. If you call from a contact list or a call history, the phone uses the default card. However, if you press and hold the green call handset, the SIM selection menu for that particular contact will open.

For frequently used numbers, you can set a priority SIM. Go to the contact card, click on the SIM select button (usually displayed as a small icon of a phone with a number 1 or 2) and choose your preferred option. Now, with quick dialing from contacts, the call will always go through the selected line, ignoring the general default settings.

You can't switch to another SIM during the conversation itself, because the channel is busy. However, if you have "Wait for a Call" enabled, you can receive a second incoming call, in which case the system will tell you whether to end the current conversation, hold it or switch, and the second line is controlled through the on-screen buttons of the call interface.

SMS and messengers for two numbers

Working with text messages on two-symbol smartphones has its own peculiarities, especially when it comes to verification codes from banks and services. the standard application "Messages" in Xiaomi allows you to view correspondence from both SIM cards in a single list, but you need to send messages from a specific number.

When you create a new message in the recipient field, you can see a small icon of the current SIM, clicking on it, you can choose which card to send SMS. Moreover, in the settings of the message application, you can set the default behavior: always ask when you send, use the main SIM or remember the choice for each particular contact, the latter option is most convenient for separating personal and work correspondence.

Special attention should be paid to messengers such as WhatsApp, Telegram or Viber, which are tied to one phone number when registering. To use two accounts of the same messenger (for example, two WhatsApp), Xiaomi smartphones have a feature called “Cloning Apps” (or “Dual Apps”).

From Settings → Apps → Dual apps, you can create a copy of the messenger you want. A second icon with a yellow corner will appear on your desktop. Once you run it, you can register for a second SIM card account, which allows you to have two active chats at once without having to constantly switch SIM cards or use third-party launchers.

Use of modem and distribution of Wi-Fi

The modem modem, which allows you to distribute Internet from your phone to other devices over Wi-Fi or USB, also obeys the rules for choosing an active SIM card for data transfer. When you turn on the access point, the smartphone uses the SIM that is selected as the main one for the mobile Internet at the moment.

If you need to distribute the Internet, and the "non-tariffed" or slow SIM is active, the result will be unsatisfactory. Before turning on the modem, be sure to check the status of the data transfer in the notification curtain or in the settings. In some versions of the firmware, when you try to turn on the access point, the system may automatically suggest switching to the SIM with the best signal.

The access point settings menu (Settings → Wi-Fi hotspot) can set a password, a network name, and, importantly, a limit on the number of devices you connect to, and it also shows you what kind of SIM card you use to distribute, and if you use your phone as a modem for your laptop, it makes sense to assign a large traffic packet Symbol to that task.

⚠️ Note: On many Xiaomi models, when using the Internet on one SIM card, the second can switch to mode 2G (EDGE) or 3G to save energy and reduce interference, which can make it difficult to receive incoming VoLTE calls to the second number.

Automation and Hidden MIUI Functions

The MIUI and HyperOS shells are famous for their customization capabilities, and SIM card management is no exception, and apart from manual switching, you can set up automatic scripts that will change communication settings depending on time, location or Wi-Fi connected.

Automatic Tasks (formerly known as Scenarios) allows you to create a rule such as: “If Wi-Fi is connected at home, turn off mobile data transfer on the second SIM” or “All calls are taken only on the working SIM during working hours.” To create such a scenario, go to Settings → Additional Functions → Automation (the path may vary slightly in different versions).

Another useful, but often overlooked, feature is the ability to set different tunes for each SIM card, which is extremely convenient to keep your phone out of your pocket and understand which number you are calling, and you can set it up in the section Sounds and Vibrations → Call Melody, where you select your audio file for each SIM.

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Use the "Flight Mode" function for one SIM. In some regions and software versions, the option to quickly turn off only one SIM card through a long press on the switch in the curtain is available, which saves charge without turning off the second line.

Also worth noting is the Smart 5G feature, which intelligently switches 4G/5G modes based on network activity, saving battery when using two active SIM cards.This feature is especially useful if one of your cards is operating in an unstable 5G coverage area, as a constant search for the network quickly drains the battery.

Troubleshooting and troubleshooting

Despite the debugging of the system, users may face problems when one of the SIM cards ceases to be determined, the network disappears or SMS does not come. Most often the problem lies in the software failure of the communication module or incorrect settings of APN (access point).

The first step should always be to restart the device. If that doesn't work, try removing the tray and wipe the SIM card contacts with soft dry cloth. Often, oxidation of the contacts or loose fit causes periodic signal loss. Make sure the card is correctly oriented in the tray according to the pattern engraved on the tray itself.

If the problem is lack of internet, check the settings of access points. APN. They must meet your operator's requirements, and you can reset them to factory values in the Settings menu. SIM-map → Name of the access point (APN) → Menu (three dots) → Reset the settings.

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If none of the SIM cards see the network, try resetting the network settings (Settings → Connection & Sharing → Reset Wi-Fi, mobile networks and Bluetooth).This will delete the saved Wi-Fi passwords, but often resolves the communication module issues.

In rare cases, especially after a firmware update, it may be necessary to re-register the device on the network, ##4636##), Go to Phone Information and temporarily switch your preferred network type to"GSM "only" and then return"LTE/TD-SCDMA/WCDMA". This will force you to restart the search network.