Invalid SIM means your phone can't use the SIM inside it. Either the phone can't read the SIM, or the mobile network won't accept it. Until you fix it, you can't make calls, send texts or use mobile data. Wi-Fi still works. The cause is usually simple: a loose or dirty SIM card, a line that isn't active anymore, or a phone that's locked to another carrier. This guide explains what an invalid SIM card means and how to fix it on iPhone and Android, at home or abroad.
What does "Invalid SIM" mean?
Your SIM (physical card or eSIM) is what links your phone to your carrier's network. When your phone says Invalid SIM, it found a SIM but can't use it. Apple shows this alert as "Invalid SIM" or "No SIM Card Installed" and gives the same checklist for both (Apple: If you see Invalid SIM or No SIM).
Similar messages point to slightly different problems:
- Invalid SIM: the SIM is there, but the phone or the network rejects it.
- No SIM or SIM card not detected: the phone can't see a SIM at all. Often the card is loose, dirty or damaged.
- SIM not supported: usually the phone is locked to another carrier.
- SIM locked or PUK required: the SIM PIN was entered wrong too many times. That's a different fix: see what a PUK code is.
Why does my phone say Invalid SIM?
These are the most common causes:
- The SIM card isn't seated well: the tray is loose, not fully closed, or comes from another phone model.
- The SIM is dirty or damaged: scratched or bent contacts, or a badly cut card.
- Your line isn't active: an unpaid bill, a new SIM that isn't activated yet, or a prepaid SIM that was disconnected after a long time without use.
- The SIM isn't registered: some countries require ID registration before a SIM works.
- Your phone is carrier-locked: it only accepts SIMs from the carrier that sold it.
- Your phone is blocked on the network: for example, it was reported lost or stolen, or it isn't registered in a country that requires it.
- Software or carrier settings are out of date.
- A hardware fault: the SIM reader in the phone is damaged.
Quick fixes to try first
Try these in order. After each one, check if your carrier's name or signal bars come back.
- Restart your phone.
- Turn Airplane Mode on, wait a few seconds, then turn it off.
- Take the SIM out and put it back. Turn off your phone, eject the tray, check the card for scratches or dirt, wipe it with a clean, dry cloth and put it back. Make sure the tray closes completely.
- Update your phone's software and, on iPhone, your carrier settings.
- Test with another SIM card, or put your SIM in another phone. This tells you if the problem is the SIM or the phone (Samsung: SIM card not working or detected). Before you swap, read what happens when you put your SIM in another phone.
- Check that your plan is active with your carrier: log in to their app or website over Wi-Fi.
How to fix Invalid SIM on iPhone
These are Apple's own steps (Apple):
1. Check your plan
Make sure you have an active plan with your carrier.
2. Check if your iPhone is locked
Go to Settings > General > About. If "No SIM restrictions" appears next to Carrier Lock, your iPhone is unlocked. If not, it only works with the carrier it's locked to.
3. Restart and check for a carrier settings update
Restart your iPhone. Then go to Settings > General > About. If an update is available, you'll see a prompt to tap OK or Update.
4. Reinsert the SIM card, or contact your carrier for an eSIM
With a physical SIM, take it out of the tray and put it back. Apple says a SIM tray from another iPhone model or another phone brand might not fit properly. If your iPhone uses an eSIM, contact your carrier. Before you reinsert it, you can clean the SIM card and the slot safely.
5. Try another SIM card
If you don't have one, ask your carrier's store to test with another SIM. You might need a replacement SIM. If the alert stays even with a working SIM, your iPhone may need service.
How to fix Invalid SIM on Android (Samsung and Pixel)
Menu names change a little between models and Android versions.
Samsung Galaxy
- Restart your phone.
- Turn it off, remove the SIM, check it for scratches or stains, clean it and the tray with a dry cloth, and put it back in line with the tray.
- Reset the mobile network settings: Settings > General management > Reset > Reset mobile network settings. Samsung warns that, depending on your carrier's settings, you might not be able to connect right after the reset.
- Still not working? Try your SIM in another phone. If it isn't detected there either, it's probably damaged, so ask your carrier for a new one (Samsung).
Google Pixel
- Go to Settings > Network & internet > SIMs, tap your carrier and make sure Use SIM is on.
- Check that the SIM is inserted correctly. If it's damaged or bent, ask your carrier for a replacement. If it's just dirty, wipe it with a microfiber cloth (Pixel Phone Help: fix connection issues).
- Reset the mobile network settings: Settings > System > Reset options > Reset Mobile Network Settings (Pixel Phone Help).
- If you still see a SIM error message, Google says to contact your carrier.
Invalid SIM after changing carrier? Your phone may be locked
If the message appears as soon as you put in a SIM from a new carrier, or a local SIM abroad, your phone is probably carrier-locked. A locked phone only works with SIMs from the carrier that sold it. On iPhone, a locked phone can also show "The SIM card inserted in this iPhone does not appear to be supported" (Apple: Unlock your iPhone).
Only your carrier can unlock it. Most carriers do it once your phone is paid off and your account meets their conditions. Here's how to check if your phone is carrier-locked and how to unlock your phone, step by step.
Deactivated, expired or unregistered SIM
Your SIM can be fine physically and still be invalid on the network:
- Prepaid SIM not used for a long time: carriers disconnect prepaid numbers that aren't used. In the UK, Vodafone and Three disconnect a pay as you go number after 180 days without a chargeable activity, and the number can't be reactivated (Vodafone UK, Three UK). Rules differ by carrier, so check yours.
- Unpaid bill or cancelled plan: your carrier may have suspended the line.
- SIM registration: in the Philippines, new SIMs stay deactivated until you register them, and unregistered SIMs are deactivated. Tourists' SIMs are valid for 30 days (SIM Registration Act, RA 11934).
- Old SIM after a SIM swap: if you moved your number to a new SIM or an eSIM, the old card stops working.
In all these cases, restarting won't help. Contact your carrier to reactivate the line or get a new SIM.
Is your phone's IMEI blocked?
Every phone has an IMEI number. Dial *#06# to see it. Networks can block a phone by its IMEI, and then no SIM will work in it:
- Lost or stolen phones: in India, a phone reported on Sanchar Saathi is blocked on all networks in the country (Sanchar Saathi). In the US, you can check an IMEI against lost or stolen reports with the CTIA Stolen Phone Checker. Buying a used phone? Check it first.
- Phones brought from abroad: some countries block foreign phones on local SIMs unless you register them. In Pakistan, visitors can register one phone temporarily, and it's suspended after 120 days (FBR). Turkey cuts off unregistered foreign phones after 120 days (BTK), and Chile after 30 days (Multibanda). More on the IMEI rule in Turkey.
In Turkey and Chile, these rules apply when you use a local SIM. Chile says you don't need to register if you only use roaming or Wi-Fi.
Invalid SIM abroad: what to do
An Invalid SIM message on a trip is stressful, because you can't call your carrier from that line. Here's what to do:
- Get on Wi-Fi first, at your hotel or a café, so you can reach your carrier through their app, website or chat.
- Do the quick fixes above: restart, Airplane Mode, reinsert the SIM.
- Using a local SIM? Check that your phone is unlocked and, where needed, that the SIM and your phone are registered.
- Using your home SIM? Ask your carrier if your line is active and if roaming is allowed on your plan.
- Using a travel eSIM? Check that it's turned on and set for mobile data, and that Data Roaming is on for it. If it still doesn't connect, read what to do when your eSIM stops working abroad or how to fix an eSIM that isn't working.
A travel eSIM won't repair your home SIM, but it can get you online while you sort it out. Your phone needs to support eSIM and be unlocked. If you also need to make and receive calls and texts in Europe, this Bouygues Telecom plan comes with a French +33 number.
Need data somewhere else? These data-only eSIMs cover Asia, the USA and Europe, and you can install them before you leave.
Asia, USA and Europe plans shown · data-only eSIMs, no phone number · Find the eSIM for your destination
When to contact your carrier
Contact your carrier if the quick fixes don't help, if a new SIM shows Invalid SIM, or if you think your line or phone is blocked. Have this ready:
- the exact message, or a screenshot,
- your phone number and account details,
- your phone's IMEI (dial *#06#),
- what you've already tried.
If another SIM works in your phone, ask for a new SIM, or ask if you can switch to an eSIM. Don't try to cut a SIM to fit a smaller tray: here's why cutting a SIM card is risky and what to do instead. Curious about short dial codes? Read what a USSD code is, with common codes and fixes.
FAQs
What does Invalid SIM mean?
It means your phone can't use the SIM inside it. The phone can't read the SIM, or the network won't accept it. You can't call, text or use mobile data until you fix it.
What is the difference between Invalid SIM and No SIM?
"No SIM" usually means the phone can't see a SIM at all. "Invalid SIM" means it sees one but can't use it. Apple gives the same steps for both: check your plan, check the carrier lock, restart, update carrier settings and reinsert the SIM.
Can an invalid SIM card be fixed?
Often, yes. A restart, a clean and reinserted SIM or a carrier settings update fixes many cases. If your line was disconnected or the SIM is damaged, your carrier has to reactivate the line or give you a new SIM.
Why does my phone say Invalid SIM with a new SIM card?
The new SIM may not be activated yet, or your phone may be locked to another carrier. Wait a little, restart, and check your carrier lock status. If it stays, ask the new carrier to check the activation.
Can an eSIM show Invalid SIM?
Yes. Apple says to contact your carrier if your iPhone with an eSIM shows this alert. Travel eSIMs can expire too: a SimOptions eSIM that you don't use within one year becomes invalid.
What should I do if my UScellular SIM says Invalid SIM?
Do the quick fixes above first. UScellular's website now redirects to T-Mobile, so contact T-Mobile support to check your line and SIM.
Does Invalid SIM mean my phone is blocked?
Not usually. Most of the time it's the SIM or the line. If every SIM shows the same error in your phone, ask your carrier if the phone is locked or if its IMEI is blocked.
