Modern smartphones are almost always equipped with two SIM card slots, which gives users flexibility in managing communications. However, the standard dialing interface is often configured to use only one primary line by default, which can be confusing if you need to place a call through a second operator. Understanding how to quickly switch between SIM cardsis a basic skill for any owner of a dual-SIM device.
In this article we will analyze in detail all the available methods for making calls from an alternative SIM card on devices running Android. We will look at both standard system features and hidden features that will help you save money or avoid communication problems in poor coverage areas. Regardless of whether you use Samsung, Xiaomi or pure Android, the principles of operation remain similar, but have their own nuances in the interface.
Standard methods for selecting a SIM card before making a call
The most obvious and common way to make a call from the desired card is to use built-in dialer (Phone application). In most modern shells, when opening a dialer, the user sees two large call buttons located next to the number entry field. They are usually marked with numbers 1 and 2 or the names of telecom operators, which allows you to intuitively select the required communication channel before pressing the green handset button.
If you have already dialed a number, but forgot to select the correct card, do not rush to hang up the call. In many versions MIUI or One UI when you press the call button, a pop-up menu appears with the question “Which SIM card to call from?” This window gives you one last opportunity to change your mind. However, it is worth remembering that in some custom firmware this menu may not appear if the priority SIM card for voice calls is hard-coded in the settings.
For those who prefer minimalism, there is a function to set the default SIM card for all outgoing calls. This is configured in the Settings → SIM cards and mobile networkssection. Here you can select the “Always ask” option or pin a specific card. Using the Always Ask mode is the safest option as it prevents accidental calls through an expensive roaming operator.
⚠️ Attention: When setting the Always Ask option, make sure that both SIM cards are active. If one of the cards is disabled in the settings or is not detected by the system, the phone may automatically use the only available line without warning, which will lead to unexpected charges.
Using the context menu in the phone book
Often the need to call from a second SIM card arises when dialing a number from the contact list or call history. In this case, the standard call button can immediately initiate a connection through the main card. To avoid this, try long pressing on a contact's name or phone number in the list. On many devices, this action opens a context menu where, in addition to the standard editing or deleting options, there are the items “Call from SIM 1” and “Call from SIM 2.”
An alternative method is to use an additional menu hidden behind three dots or the “i” (information) icon next to the phone number. When you open a contact card, you will see interaction history and action buttons. If you click on the arrow next to the handset button or select an item from the drop-down list, the system will prompt you to select the preferred network for that particular call. This is especially convenient if you negotiate with one subscriber exclusively through a working operator.
Some users prefer to sort contacts into groups or add notes to names in order to visually remember which SIM card is used to communicate with a particular person. Although this is not a technical solution, this approach helps reduce cognitive load and minimize errors when dialing a number in a hurry. It is also important to check the contact display settings to make sure that duplicate numbers from different SIM cards are not merged into one entry without the ability to select a source.
If you have several numbers of one person recorded in your contact, the Android system can remember your last SIM choice for each specific number and offer it automatically next time.
Setting up call rules for different situations
Advanced users can set up more complex scenarios for using two SIM cards using the built-in smart network selection functions. In the SIM card settings menu there is often a section “Call Rules” or “Smart SIM Selection”. Here you can set the conditions under which the phone will automatically switch to the second line. For example, you can set a rule: “If the first SIM card is not online, use the second one.” This ensures that you will always be connected, even if the main operator has lost the signal.
Another useful function is to link the SIM card to the connection type. You can configure the device so that all calls to short numbers or support services are automatically made from the card that has the most favorable tariff or a free package of minutes. To do this, in the call settings, select the option “For short numbers” or “For international calls”, where the preferred line is indicated. This approach allows you to optimize costs without the need for manual switching before each important call.
It is also worth paying attention to the “Preferred SIM for data” function, which indirectly affects the operation of VoLTE (Voice over LTE). If you make calls via Internet protocol, the quality of the connection will depend on which card is currently selected for data transfer. Switching the main Internet channel may require rebooting the communication module or briefly disconnecting the connection, so plan such changes in advance if you are expecting an important call.
| Use scenario | Recommended setting | Advantage |
|---|---|---|
| Daily communication | Main SIM (cheap tariff) | Budget saving |
| Business negotiations | Second SIM (corporate tariff) | Stream sharing |
| Calls for border | SIM with roaming package | Reduced cost per minute |
| Emergencies | Any available network | Connection guarantee |
Specifics of interfaces from different manufacturers
Although the core of the system Android is the same for everyone, smartphone manufacturers often make their own changes to the interface of the “Phone” application, which affects the availability of SIM card switching functions. For example, in smartphones Xiaomi with a shell MIUI SIM card selection buttons are located directly below the number entry field and are clearly color-coded (blue and orange). The user can even customize these colors in accordance with operator brands for greater convenience.
In devices Samsung with a shell One UI the logic is slightly different: when dialing a number, the SIM card buttons may be less visible or hidden behind an additional menu if the simplified interface mode is enabled. In such cases, you need to go to the settings of the Phone application itself and activate the display of network selection buttons. Also Samsung implemented the “Bixby Routines” function, which allows you to create automatic scenarios, for example, switching the main SIM card to a working one when connecting to a Wi-Fi network in the office.
Smartphones from Google (Pixel series) and other devices with a clean Android offer the most concise interface. Here, the choice of SIM card is carried out through the pop-up menu above the call button, which appears automatically if the default card is not set. The absence of unnecessary visual information makes the typing process quick, but requires more attention from the user, since the selection buttons are not always in the field of view at a quick glance at the screen.
Secret function in some firmware
In a number of custom firmware (for example, LineageOS) it is possible to assign different ringtones for incoming calls to the first and second SIM cards. This allows you to instantly understand which line you are being called on, without looking at the screen, just by the sound.
Switching problems and their solutions
Sometimes users are faced with a situation where the phone does not allow you to select a second SIM card for a call, blocking this opportunity or giving an error. The most common reason is the activation of the “4G/LTE Only” mode for one of the cards in the network settings. In some implementations DSDS (Dual SIM Dual Standby), the second card may temporarily turn off or switch to 2G/3G mode during a conversation on the first, which makes it impossible to make an outgoing call from it at this moment.
Another common problem is frequency incompatibility or lack of VoLTE support from a second operator in your region. If the second SIM shows as "No Service" or "Emergency Calls Only", attempting to make a call through it will be unsuccessful, regardless of the settings selected. In this case, you need to check the card in another slot or update the network profile through the mobile operator settings.
It is also worth considering the hardware limitation: in some budget models, the second slot is hybrid and supports only memory cards or SIM cards of a certain format. If a non-standard size card is installed in this slot via an adapter, the contact may be unstable, resulting in failures when attempting to initiate a call. In such cases, the system can automatically redirect the call to the main card, ignoring the user's choice.
⚠️ Attention: If you are using old SIM cards, hand-cut from larger format cards, make sure that the contacts are not damaged. An unstable contact in the second slot often results in the phone seeing the card, but cannot register on the network to make outgoing calls.
☑️ Diagnosing problems with the second SIM card
Subtleties of roaming and international calls
When you are abroad, the issue of choosing a SIM card becomes critically important from a financial point of view. Many operators offer special roaming packages for only one of the SIM cards, while the second one can be charged at standard, extremely high rates. Before making any call while roaming, it is strongly recommended to manually select a SIM card with an activated travel tariff, even if the main card is configured by default.
Modern smartphones support the function of automatically switching to a local network when a more favorable tariff is detected, however, this function does not work in all countries and not with all operators. The safest thing to do before your trip is to keep a strict rule in your phone settings: “International calls - SIM 2 only” (where a local or roaming card is installed). This will eliminate the human factor and protect your account from unexpected expenses.
The technology deserves special attention eSIM, which allows you to use a virtual second SIM card alongside a physical one. When setting up an eSIM for international travel, it is important to label it correctly (for example, Travel) so that Android can correctly suggest it for calls in appropriate scenarios. The eSIM management interface is usually located in the same section of settings as managing physical cards, and provides the same options for selection before making a call.
When roaming, always manually check the selected SIM card before pressing the call button, as automatic rules may fail if you change country or operator.
Frequently asked questions (FAQ)
Is it possible to make a call from the second SIM card if the first one is busy with a conversation?
Yes, in most modern smartphones that support the technology DSDS (Dual SIM Dual Standby) you can make and receive calls to the second SIM card while the first one is busy. However, it is worth considering that during a conversation on one line, the second may temporarily lose the ability to receive incoming data or go into standby mode, depending on the implementation of the network by the operator.
Why does the phone not show the SIM card selection button when dialing a number?
This can happen for two reasons: either the “Main SIM” is hardcoded in the settings for all voice calls, or one of the SIM cards is not active/not detected. Check the section Settings → SIM cards and make sure that the “Always ask” switch is active or select the desired card manually before calling.
Does the choice of SIM card affect the sound quality during a call?
Sound quality does not depend on the slot number, but on the communication technology supported by a specific SIM card and operator in a given area. If one of the cards supports VoLTE (calls via 4G), and the other does not, then the call through the first one will sound much clearer. The choice of SIM card in this case directly affects the quality of the connection.
How to make contacts open immediately with the choice of SIM card?
In the standard Contacts application, this behavior often depends on the application settings. Go to the settings of the dialer or phone book and find the item “Action when calling from contacts”. Set it to “Select every time” or similar so that the system does not use the default card without your knowledge.
Is it possible to assign different ringtones to different SIM cards?
Yes, this function is available in the sound settings of most smartphones. In the section Sounds and vibration → Ringtone usually it is possible to select a separate ringtone for SIM 1 and SIM 2. This helps to instantly identify the line on which an incoming call is received without looking at the screen.