Mobile Phones iPhone & iOS 323 323 people found this article helpful What to Do When Your iPhone Says "No SIM" How to fix the No SIM Card Installed error by Sam Costello Writer Sam Costello has been writing about tech since 2000. His writing has appeared in publications such as CNN.com, PC World, InfoWord, and many others. our editorial process Facebook Twitter Sam Costello Updated on May 31, 2020 iPhone & iOS Switching from Android Tweet Share Email If your iPhone is displaying a No SIM Card Installed error, then you can't connect to your wireless carrier's network. This means you can't use your wireless data over 4G or 5G, and that you can't make or receive calls. Besides your iPhone alerting you with an error message, you'll know your iPhone is having a problem with its SIM card if the carrier name and signal bars/dots at the top of the screen are missing, or have been replaced by messages like No SIM or Searching. Bailey Mariner / Lifewire Causes of iPhone No SIM Error There are a number of reasons for the iPhone No SIM error. It could be that the iPhone doesn't recognize its SIM card, which is used to connect to these networks. This problem can also be caused by your SIM card becoming slightly dislodged or a problem with your phone's software. The "No SIM" error can be displayed in multiple versions, including: No SIM.No SIM Card Installed.Invalid SIM.Insert SIM. Whatever the cause and the type of error, the solution is pretty easy: All you need to fix this is a paper clip and some software settings. Here's what to do if your iPhone says "No SIM." These instructions apply to all iPhones. How to Find the iPhone SIM Card To fix SIM card issues, you have to know where the SIM card is (if you want to learn a lot more about what the SIM card is and what it does, check out What is an iPhone SIM Card?). The location depends on your iPhone model. iPhone, iPhone 3G, and iPhone 3GS: Look between the sleep/wake button and the headphone jack at the top of the phone for a slot with a tiny hole in it. This is the tray that holds the SIM card.iPhone 4 and newer: On the iPhone 4 and newer, the SIM tray is on the right side of the phone, near the sleep/wake (or Side) button. The iPhone 4 and 4S use a microSIM. Later models have the slightly smaller, more-modern nanoSIM. 1:39 What's a SIM Card and How Does It Work? How to Fix the iPhone "No SIM" Error If your iPhone is displaying the No SIM error, or you don't have any cellular bars when you should, try these steps, in this order, to fix the problem. Remove the iPhone SIM card and re-seat it. Since the No SIM problem is often caused by the SIM getting slightly dislodged, the first fix is to try to put it back in place and make sure it's fully seated. After a few seconds (wait up to a minute), the No SIM Card Installed error should disappear and your regular bars and carrier name should re-appear at the top of the iPhone's screen. If it doesn't, remove the SIM and check if the card or the slot is dirty. If they are, clean them. Blowing into the slot is probably OK, but a shot of compressed air is always best. Restart iPhone. If your iPhone still doesn't recognize the SIM, try the all-purpose fix for many iPhone problems: a restart. You'd be surprised how many issues are solved by restarting. Turn Airplane Mode On and Off. If you're still seeing the SIM error, your next step is to turn Airplane Mode on and then off again. Doing this can reset the iPhone's connection to cellular networks and may resolve the problem. Update iOS. If the problem continues to persist, check to see if there's an update to the iOS, the operating system that runs on the iPhone. You'll want to connect to a Wi-Fi network, or a computer, and have a decent amount of battery life before you do this. Install any available updates and see if that solves the problem. Make sure your phone account is valid. It's also possible that your phone company account isn't valid. In order for your phone to be able to connect to a phone company network, you need a valid, active account with a phone company. If your account has been suspended, canceled, or has some other problem, you may see the SIM error. Check for an iPhone Carrier settings update. Another culprit behind the SIM not being recognized could be that your phone company has changed the settings for how your phone connects to its network and you need to install them. Test for a malfunctioning SIM card. If your iPhone still says it has no SIM, your SIM card could have a hardware problem. One way to test this is by inserting a SIM card from another cell phone that you know works fine. Make sure to use the correct size—standard, microSIM, or nanoSIM—for your phone. If the No SIM Card Installed warning disappears after inserting another SIM, then your iPhone SIM is broken. You can get a new one from Apple or your phone company. If nothing works, contact Apple tech support or make an Apple Store appointment. If all of these steps don't solve the problem, you have a problem that you can't fix.