Replacing a SIM card on a smartphone with Android is a procedure that seems simple only at first glance. Many users encounter unpleasant surprises: missing contacts, lost messages, or even blocked messenger accounts. The reason lies in the fact that SIM card not only provides communication, but also stores some of the critical data - from the phone book to authorization keys for some services.

In this article we will analyze how to prepare the phone for replacing a SIM cardso as not to lose a single byte of information. You will learn what data is tied to the SIM, how to transfer it to a new device or to the cloud, and what to do if something stops working after replacing the card. We will pay special attention to the nuances for different manufacturers - Samsung, Xiaomi, Honor and others, since they may have different synchronization settings.

Important: if you plan not only to change the SIM, but also switch to another operator (for example, from MTS to Tele2), some of the instructions will concern this scenario. We will also look at how to avoid problems with two-factor authentication (2FA) in banks and social networks, which is often tied to a phone number.

What data is stored on the SIM card and what can be lost

Many people mistakenly think that a SIM card is only needed for calls and mobile data. In fact, it stores:

  • 📞 Contact (if they are saved on SIM, and not in the phone memory or Google account).
  • 💬 SMS and MMS (on some older models or with specific settings).
  • 🔑 Authentication keys for banking applications, instant messengers (for example, WhatsApp or Telegram).
  • 📡 Network settings (APN, roaming parameters - rarely, but it happens).
  • 📱 Linking to accounts (some services use the phone number as an identifier).

The most common problem is loss of contacts saved directly to the account. SIM cardThey are not visible in Google Contacts, and they are not synchronized automatically. If you do not make a backup copy, after removing the old SIM, these numbers will disappear forever.

Another trap - two-factor authentication (2FA). Many services (from VKontakte to Sberbank Online) link your account to your phone number. When you change your SIM (and even more so, your operator), you may lose access if you do not reconfigure 2FA in advance.

⚠️ Attention: On some tariffs, operators block Internet access when replacing a SIM before activating a new card. Check this point with your provider so as not to be left without communication at the most inopportune time. moment.

Preparation of the phone: backup before replacing SIM

The first and most important step is create backup copies of all data, which may be affected.

Saving contacts

If your contacts are stored on a SIM card, they need to be transferred to Google Account or exported to a file. You can do this like this:

  1. Open the application Contact.
  2. Click on the three dots (⋮) → Manage contacts → Import/export.
  3. Select Export to device (the file will be saved .vcf) or Synchronize with Google.

On Samsung path can differ: Contacts → ⋮ → Settings → Manage contacts → Import/export.

Export contacts from SIM to .vcf file|

Synchronize contacts with Google Account|

Check that all numbers are displayed in the web version of Google Contacts (contacts.google.com)|

Delete duplicate contacts (if any)-->

Backup SMS and call logs

SMS and call history are usually stored in the phone's memory, but they too worth saving. To do this:

  • 📱 Use the built-in backup function in Settings → Google → Backup (enable the option SMS i Call log).
  • 💾 Install third-party applications like SMS Backup & Restore (saves messages in an XML file on Google Drive).
  • 📧 Export important SMS manually (screenshots or forward to email).

On Xiaomi and some other brands have their own backup tools in Settings → Advanced → Backup and reset.

⚠️ Attention: If you use WhatsApp or Viberlinked to a phone number, be sure to back up your chats in the settings of these applications. When changing SIM (especially with a change in number), access to the account may be blocked!

Transferring data from SIM to a new card

If you just change the physical SIM card to the same (for example, to a nano-SIM instead of a micro-SIM), but same number, there is no need to transfer data - the operator will copy all the information to the new card automatically. However, if you:

  • 🔄 Change phone number (for example, when changing operator).
  • 📱 Go to eSIM (virtual SIM card).
  • 🔄 You receive a new SIM with the same number, but without automatic data transfer (rare, but happens with some operators).

...then you will have to transfer contacts and settings manually.

How to transfer contacts to a new one SIM card

If your new SIM supports storing contacts (not all modern cards can do this), do the following:

  1. Export contacts from the phone to a file .vcf (as described above).
  2. Insert the new SIM into the phone.
  3. Open Contacts → ⋮ → Manage contacts → Import/export → Import from device.
  4. Select file .vcf and specify the target - SIM card.

On Honor i Huawei the path may look like this: Contacts → ⋮ → Settings → Import/export → Import from memory phone.

Manufacturer Path to import/export contacts Features
Samsung Contacts → ⋮ → Managing contacts → Import/export Supports export to SD card
Xiaomi Contacts → ⋮ → Settings → Import/export contacts May require permission to access files
Google Pixel Contacts → ⋮ → Settings → Import → From device Automatically suggests saving to Google Account
Honor/Huawei Contacts → ⋮ → Settings → Import/export Supports import from two SIMs simultaneously

On most modern Android smartphones, contacts are saved by default to a Google Account, not to a SIM card. If you haven't changed this setting manually, your contacts are already safe and linked to an email, not a physical card.

On a SIM card|

To Google Account|

In the phone memory|

I use another service (iCloud, Yandex, etc.)|

Setting up the network and APN after replacing the SIM

After installing a new SIM card, the phone may not connect to the mobile network. Most often this is due to incorrect APN settings (Access Point Name) - parameters that determine how the device connects to the operator's Internet.

In most cases, APN settings are sent automatically via SMS from the operator, but sometimes you have to enter them manually. Here's how to do it:

  1. Go to Settings → Network and Internet → Mobile network → Advanced → Access points (APN).
  2. Click + (Add APN) or select existing profile.
  3. Enter the data provided by your operator. Usually this is:
Name: MTS Internet (or the name of your operator)

APN: internet.mts.ru (example for MTS)


Proxy: not specified


Port: not specified


Username: mts


Password: mts


Authentication type: PAP or CHAP


APN type: default,supl

For other operators, the parameters will be different. For example, Beeline APN usually internet.beeline.ru, and Tele2 — internet.tele2.ru.

⚠️ Attention: If the Internet does not work after manually entering the APN, restart the phone. Sometimes changes are applied only after a reboot.
💡

If you don’t know the APN parameters for your operator, call support or check the official website. Usually there is a section "Internet Settings" with instructions for different phone models.

Problems with instant messengers and banking applications

One ​​of the most unpleasant situations when changing SIM is account blocking in instant messengers and banking applications. This happens because many services use a link to a phone number for two-factor authentication (2FA).

WhatsApp and Telegram

If you change phone number (not just the SIM card, but the number itself), to WhatsApp i Telegram you will have to transfer your account:

  • 📱 To WhatsApp: Settings → Account → Change number. Follow the instructions to transfer your chat history.
  • 💬 V Telegram: the number is tied to the account, but you can change it in Settings → Change phone number. The chat history will be saved if you use cloud storage.

If you do not change the numberonly have a SIM card, then after activating the new card, messengers should work without additional actions. However, sometimes re-activation is required (entering the code from SMS).

Banking applications and 2FA

The situation with banks is more complicated. Many of them (for example Sberbank Online, Tinkoff, VTB) link your account to a phone number and SIM card. When replacing a card:

  1. Make sure you have backup access codes or backup codes for 2FA.
  2. If the number does not change, after installing a new SIM, simply confirm the entry with the code from SMS.
  3. If the number changes, in advance update it in your bank account or contact support.

Some banks (for example, Alfa-Bank) allow you to link your account to an email instead of a phone number - this is a good way to avoid problems when changing SIM.

What to do if the banking application is blocked after changing the SIM?

If after replacing the SIM you cannot enter the banking application, try:

1. Restart the phone and try entering again.

2. Restore access through the backup code (if it was saved).

3. Contact bank support through another channel (for example, through the web version of your personal account or by calling a hotline).

4. Visit a bank branch with your passport to restore access.

Some banks block access when changing SIM for security purposes, so check with them in advance about the procedure for updating the linked number.

Features for different smartphone manufacturers

Each brand has its own nuances of working with SIM cards. Let's look at the most common ones.

Samsung

Devices Samsung (for example, Galaxy S23, A54) have a built-in utility Samsung Smart Switch, which helps you transfer data, including contacts and SMS, to a new SIM or another phone. To use it:

  1. Install Smart Switch with Google Play (if not installed by default).
  2. Connect to Wi-Fi or another phone via cable.
  3. Select Data transfer → SIM card and follow the instructions.

Also Samsung allows you to save contacts to your own account Samsung Account, which is convenient if you use the brand’s ecosystem.

Xiaomi, Redmi, POCO

On smartphones Xiaomi (for example, Redmi Note 12, POCO X5) there is a function Clone applicationsthat can be useful if you use two SIM cards. However, for backup it is better to use the built-in utility:

  1. Go to Settings → About phone → Backup and reset.
  2. Select Local backup or Cloud backup (in Mi Account).
  3. Make sure the option is enabled in the settings Contact and SMS.

Please note: by Xiaomi by default, contacts can be saved in Mi Account, and not in GoogleCheck this in the settings. synchronization.

Google Pixel

Devices Google Pixel are maximally integrated with Google services, so it’s easiest here:

  • All contacts are saved by default in Google Contacts.
  • SMS and call log are backed up via Settings → Google → Backup.
  • When replacing a SIM, just insert a new card - all data will be pulled from the cloud automatically.

If you use Pixel, make sure that you have synchronization enabled in Settings → Accounts → Google → Synchronization account.

Honor and Huawei

Smartphones Honor and Huawei (for example, Honor 90, Huawei P60) have their own ecosystem Huawei Mobile Services (HMS). It is important here:

  • Contacts can be saved in Huawei ID instead of Google.
  • For backup, use Settings → System → Backup and Restore.
  • When When replacing a SIM, check the settings Mobile data → Access Points (APN)as they may be reset.
⚠️ Attention: On some models Huawei without Google services (for example, Mate 50) data transfer may vary. Use Huawei Backup or physical transfer via cable.

What to do if something does not work after replacing the SIM

Even if you did everything correctly, problems may arise after replacing the SIM. Let's look at the most common ones and ways to solve them.

Problem Possible cause Solution
No mobile network Incorrect APN or SIM settings activated Check the APN (see section above) or restart the phone. If it doesn't help, contact your operator.
SMS are not coming The SMS message center has reset or the SIM does not support SMS Check the SMS center number in the message settings or request it from the operator.
Calls are not working SIM is not activated or blocked Call the operator's short number (for example, *111# for MTS) or check your balance.
Missed contacts Contacts were saved on the old SIM and not transferred Restore them from a backup (.vcf file) or check synchronization with Google.
mobile data does not work Data transfer is disabled or incorrect APN Turn on mobile data in the notification shade and check the APN.

If none of the solutions helped, try:

  1. Remove and reinsert the SIM card (sometimes the contacts oxidize).
  2. Check the SIM in another phone - if it doesn’t work there, the problem is on the operator’s side.
  3. Reset network settings: Settings → System → Reset → Reset network settings.

On Samsung and some other brands there is a function Airplane mode with subsequent activation - this can “wake up” the communication module if it is frozen.

💡

If, after replacing the SIM, banking applications or instant messengers stop working, first check if you receive an SMS with a confirmation code to the new number. If not, the problem is on the operator's side. If it arrives, but the application does not accept the code, contact the service support.

FAQ: Frequently asked questions about replacing SIM on Android

Is it possible to transfer contacts from a SIM to a new card without a phone?

No, to transfer contacts from a SIM to a new card you need a phone, since it is through it that data is read and written. However, you can:

  1. Insert the old SIM into any phone, export contacts to a file .vcf.
  2. Insert a new SIM into the same phone and import contacts from the file.

If you do not have a second phone, contact a communication store - they can help with the transfer.

What happens if you insert a new SIM without removing the old one?

If your phone supports two SIM cards (Dual SIM), you can use both at the same time. However:

  • Contacts from the old SIM will not be transferred automatically.
  • Some operators may block one of the cards if they are from the same provider (for example, two SIMs from MTS).
  • SMS and calls will be sent to the SIM that is configured by default.

If the phone does not support Dual SIM, it simply will not see the second card.

How to transfer data from SIM to eSIM?

Transferring data from physical SIM to eSIM depends on the operator. General algorithm:

  1. Activate eSIM through the operator's application (for example, My MTS, My Beeline).
  2. Export contacts from the SIM to the phone (as described above).
  3. Remove the physical SIM and use the eSIM for communication.

Contacts and SMS are transferred to the phone, not to the eSIM, since the virtual card does not store data.

Why do some applications not work after replacing the SIM?

This may be related with:

  • Binding an application to a phone number (for example, banking applications or WhatsApp).
  • Changing IMEI or network settings (rare, but happens on some models).
  • Blocking by an operator (for example, if the SIM is not activated).

Solution:

  1. Reboot the phone.
  2. Check whether SMS are received (if not, the problem is with the operator).
  3. Update the application or reinstall it.
Can I use an old SIM after activation new?

It depends on the operator:

  • If you change the number, the old SIM is usually deactivated.
  • If you change only the card (for example, from micro-SIM to nano-SIM), but the number remains the same, the old SIM stops working after activating the new one.
  • Some operators allow use both SIMs at the same time (for example, the main and backup), but this needs to be clarified at the communication store.

To avoid problems, it is better to check with the operator whether the old SIM will be blocked.