Have you just bought a new smartphone on Android or decided to change the SIM card, but are not sure which side to insert it into the tray correctly? This seemingly simple procedure can cause confusion - especially if you are encountering it for the first time. An error when installing a SIM card can lead to the phone not receiving the network, and in the worst case, damaging the contacts on the card or in the device itself.

In this article we will look at how to determine the correct side for installation nano-SIM, micro-SIM or eSIM (if yours Android supports it), what types of trays there are and how to avoid common mistakes. You will also learn what to do if the SIM card is not recognized after installation, and how to check whether it is inserted correctly without contacting a service center.

The material is relevant for all modern smartphones - from budget Xiaomi Redmi and Samsung Galaxy A to flagships Google Pixel i OnePlus. Even if your model was released several years ago (for example, Huawei P30 2019), the instructions will remain the same - the principles for installing SIM cards have not changed since 2018.

Types of SIM cards: how to determine which one is suitable for your Android smartphone

Before inserting a SIM card, you need to make sure that its size matches the tray of your phone. Today there are three main form factors:

  • 📱 Nano-SIM (12.3 × 8.8 mm) - the most common standard for smartphones after 2015. Used in Samsung Galaxy S23, Google Pixel 7, Xiaomi 13 and most other modern models.
  • 📱 Micro-SIM (15 × 12 mm) - found in older devices (until 2014–2016), for example, Samsung Galaxy S5 or HTC One M8. Today it is almost never used.
  • 📱 eSIM (built-in) - a virtual SIM card that does not need to be physically inserted. It is supported in Google Pixel 6/7/8, Samsung Galaxy S22/S23/S24 (only in some regions) and iPhone (but this is not our case).

If you have universal SIM card (with perforation for all sizes), carefully squeeze out the desired format. Never cut the card with scissors - this can damage the chip and make it unusable. It is better to contact the operator's communication shop (MTS, Beeline, MegaFon, Tele2), where they will replace your card with the correct size for free.

To find out what type of SIM your smartphone supports, check:

  • 🔍 Instructions to your phone (section “Installing a SIM card”).
  • 🔍 SIM tray - usually there is a marking on it (for example, Nano-SIM or an image of a card of the required size).
  • 🔍 Model characteristics on the manufacturer's website (for example, Xiaomi or Samsung).
⚠️ Attention: Some smartphones (for example, Samsung Galaxy S22 Ultra or iPhone 14) support hybrid trays, where you can insert either two nano-SIMs or one nano-SIM + memory card microSD. Make sure you are inserting the card into the correct slot!

Which side to insert the SIM card into the tray: the “golden angle” rule

The most important question is how to determine which side to insert the SIM card in Android. A simple rule works here:

  • 🔹 The microcircuit (gold contacts) should be face down (to the back cover of the phone).
  • 🔹 Beveled corner on the card should coincide with the beveled corner on tray.

Visually it looks like this:

  1. Take the SIM card so that the chip is at the bottom, and the beveled corner is in the upper left corner.
  2. Put the card on the tray: the contacts should “look” down, and the beveled corners coincide.
  3. By lightly pressing, make sure that the card “sits” into the grooves and does not dangle.

If you mix up the side, the SIM card will either not fit into the tray, or (worse) damage the contacts when you try to insert it by force. Never do not put pressure on the card - it should go in easily!

📊 What smartphone do you have?
Samsung
Xiaomi
Google Pixel
Honor/Huawei
Other
Smartphone model SIM card type Tray features
Samsung Galaxy S23/S22/S21 Nano-SIM (or eSIM) Hybrid tray: nano-SIM + nano-SIM or microSD
Xiaomi Redmi Note 12/11 Nano-SIM Two slots for nano-SIM, without microSD support
Google Pixel 7/6 Nano-SIM or eSIM One physical slot (nano-SIM) + eSIM support
Honor 90/80 Nano-SIM Two slots for nano-SIM, without microSD

If your smartphone supports dual SIM cards, pay attention to the tray markings. Usually slots are numbered (SIM 1 and SIM 2), and the first SIM card is considered the main one (for calls and SMS by default). In some models (for example Xiaomi), you can set the priority in the menu Settings → SIM cards and mobile networks.

Step-by-step guide: how to insert a SIM card into Android

Now let's move on to practice. Here are universal instructions that are suitable for 99% of smartphones Android:

Turn off the phone (recommended, but not required)

Check the type of SIM card (nano/micro)

Find the SIM tray (usually on the top or side edge)

Prepare a paper clip or tool to remove the tray-->

  1. Turn off the phone.

    This is not necessary, but is recommended to avoid failures when recognizing the card. Press and hold the power button, then select Power.

  2. Locate the SIM card tray.

    It is usually located:

    • 📍 On top edge (for example, Samsung Galaxy S23, Google Pixel 7).
    • 📍 On right side edge (for example, Xiaomi Redmi Note 12, Honor 80).
    • 📍 On left side edge (rarely, for example, Sony Xperia).

The tray looks like a small hole with a hole for a paper clip.

  • Remove the tray.

    Take paperclip (or a special tool included with the phone), insert it into the hole and lightly press until the tray comes out. Do not use excessive force!

  • Place the SIM card in the tray.

    Follow the “golden angle” rule: contacts down, the beveled corner of the card matches the beveled corner of the tray If there are two trays. SIM cards, insert the first card into the slot SIM 1.

  • Insert the tray back.

    Gently push it in until it clicks. Make sure that it sits straight - if the tray is crooked, remove it and try again.

  • Turn on the phone.

    Wait for the system to boot. If everything is done correctly, a network indicator will appear in the top panel (for example, MTS or 4G).

    • If after turning on the phone the network does not appear, check:

    • 🔄 Is the SIM card inserted correctly (remove the tray and check again times).
    • 🔄 Is the mobile network enabled in the settings (Settings → SIM cards and mobile networks → Mobile data).
    • 🔄 Is the SIM card blocked (for example, if you haven’t used it for a long time).
    💡

    If the tray does not extend, do not try to remove it by force - contact the service center. The mechanism may be jammed or broken.

    What to do if the SIM card is not recognized after installation

    Sometimes, even with proper installation, the smartphone does not see the SIM card. Here are the most common reasons and ways to eliminate them:

    Problem Possible cause Solution
    The phone does not see the SIM card The card is inserted on the wrong side Turn over the card (contacts down, the beveled corner matches)
    No network or “SIM card is not inserted” The tray is not fully inserted Remove and reinsert the tray until it clicks
    The SIM card is recognized, but not Internet Mobile data is not configured Check the APN settings (Settings → Mobile network → Access points (APN))
    The phone is asking for a PUK code SIM card is blocked after entering the PIN incorrectly Enter the PUK code (indicated on the plastic SIM holder or from the operator)

    If none of the methods helped, try:

    1. Insert the SIM card into another phone to check its functionality.
    2. Clean the tray contacts from dust or oxidation using soft brush or alcohol wipes.
    3. Update the phone firmware (Settings → System → System update).
    4. Reset network settings (Settings → System → Reset → Reset network settings).
    ⚠️ Attention: If after all the manipulations the SIM card still does not work, it is possible physical defect for example, damage to the contacts on the card or in the tray. In this case, contact the service center or operator for a SIM replacement.

    Although the principle of installing a SIM card is the same for most smartphones, some models have nuances: Let's look at the most popular ones:

    Samsung Galaxy S23/S22/S21 and other flagships

    For these models hybrid tray: you can insert either two nano-SIM or one nano-SIM + memory card microSDPlease note:

    • 🔹 If you use two SIM cards, the second SIM card does not support 5G (4G only).
    • 🔹 Memory card microSD and second SIM card incompatible —you will have to choose one.

    Xiaomi Redmi Note 12/11, POCO X5

    In most models Xiaomi the tray is located on right side edge. Features:

    • 🔹 Two nano-SIM are supported, but no microSD slot.
    • 🔹 In some regions (for example, India) versions with a separate slot for microSD are sold.

    Google Pixel 7/6/5

    The Pixel tray is located on left side edge. Important:

    • 🔹Only one physical nano-SIM is supported + eSIM.
    • 🔹 In the USA, some models are sold only with eSIM (without physical slot).

    Honor 90/80/70

    Tray on right edge, two nano-SIM are supported. Feature:

    • 🔹 Chinese versions may not have support 4G/5G bands for Russian operators.
    What to do if the tray for SIM cards?

    If the tray eject mechanism is broken (for example, the spring has popped out), do not try to repair it yourself - this may damage the motherboard. Contact the service center. The cost of replacing the tray usually does not exceed 1,000–1,500 rubles (as of 2026).

    Frequent mistakes when installing a SIM card and how to avoid them

    Even experienced users sometimes make mistakes when installing a SIM card. Here are the most common ones:

    • ❌ Insert the card with the contacts facing up.

      This is the most common mistake. Remember: the contacts always face down!

    • ❌ Use force when installing the tray.

      If the tray does not go in easily, the card is not inserted correctly. Do not press - this can bend the contacts.

    • ❌ Do not align the beveled corners.

      The beveled corner on the card must coincide with the beveled corner on the tray. If you mix it up, the card will not fit into the slots.

    • ❌ Insert the micro-SIM into the nano-SIM slot.

      Even if the card physically fits, it will not work due to mismatched contacts.

    • ❌ Do not turn off the phone before installation.

      Although this is not necessary, it is better to turn off the device to avoid failures.

    To avoid problems, follow a simple algorithm:

    1. Check the type of SIM card (nano/micro).
    2. Align the beveled corners.
    3. Make sure that the contacts are facing down.
    4. Insert the tray with a slight movement until it clicks.
    💡

    If the SIM card is not recognized, first check that it is inserted correctly. In 90% of cases, the problem is precisely this, and not a malfunction of the phone or card.

    eSIM in Android: an alternative to a physical SIM card

    If your smartphone supports eSIM (electronic SIM card), you can do without physical media. This is convenient if:

    • 🔹 You often change operators or tariffs.
    • 🔹 You want to use two SIM cards, but the phone only has one physical slot.
    • 🔹 You travel and buy local SIM cards.

    To activate eSIM on Android:

    1. Make sure that your phone supports eSIM (a list of models is on the operator's websites).
    2. Get QR activation code or activation code from your operator (MTS, Beeline, MegaFon, Tele2).
    3. Go to Settings → SIM cards and mobile networks → Add mobile tariff → Download SIM card.
    4. Scan the QR code or enter the activation code.
    5. Wait a few minutes for eSIM is activated.

    Advantages of eSIM:

    • ✅ There is no risk of damaging the physical card.
    • ✅ You can quickly switch between tariffs.
    • ✅ A slot is freed up for a second physical SIM or memory card.

    Disadvantages:

    • ❌ Not all operators and phone models support eSIM.
    • ❌ When you reset your phone to factory settings, the eSIM may be deactivated.
    ⚠️ Attention: Before switching to eSIM, check with your operator to see if this feature is supported in your region. For example, Tele2 i Iota eSIM is not offered in all cities.

    FAQ: Answers to frequently asked questions about SIM cards in Android

    Is it possible to insert a micro-SIM into the nano-SIM slot using an adapter?

    No, this will not work. Although the card may physically fit, the contacts will not match and the phone will not recognize it. If you only have a micro-SIM, contact your operator for a replacement with a nano-SIM (usually free of charge).

    What should you do if the SIM card tray is jammed and does not eject?

    Do not try to pull it out by force - this can damage the mechanism. Try:

    1. Use a thinner tool (for example, a needle instead of a paper clip).
    2. Heat the phone a little (for example, keep it in a warm place) - sometimes this helps if the tray is jammed due to moisture.
    3. Contact a service center.
    Why does the phone see the SIM card, but there is no network?

    Possible reasons:

    • 🔹 Mobile data is disabled - check the settings (Settings → SIM cards and mobile networks → Mobile data).
    • 🔹 Incorrect APN settings —request them from the operator or find them on the Internet (for example, “APN MTS for Android”).
    • 🔹 Problems with the operator —check if technical work is underway.
    • 🔹 SIM card is blocked —if you entered the PIN incorrectly three times, you will need a PUK code.
    Can I use two SIM cards from different operators in one phone?

    Yes, if your smartphone supports Dual SIM (two SIM cards). At the same time:

    • 🔹 Usually only one SIM card can work in a 4G/5G network, the second - only 2G/3G.
    • 🔹 You can choose which SIM card is used for calls, SMS and mobile data in the settings.

    Exception: some flagships (for example, Samsung Galaxy S23 Ultra) support Dual 5G, but this depends on the region and firmware.

    What happens if you insert the SIM card the wrong way?

    If you If you try to insert a card with the contacts facing up or an incompatible size (for example, a micro-SIM into a nano-SIM slot), then:

    • 🔹 Phone does not recognize card.
    • 🔹 Possibly damage to the contacts on the card or in the tray (if you apply force).
    • 🔹 In rare cases, it may jam the tray.

    If you realize that you inserted the card incorrectly, do not turn on the phone —immediately remove the tray and reinstall the SIM.