The safety reason TSA might ask you to turn on your phone

CBP can take this a step further and search your phone.

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You may have heard about Transportation Security Administration (TSA) agents asking someone to turn their smartphone on while going through security at an airport and think this is something new — but it isn't. This ruling about turning on devices before boarding has been in place since 2014. Back then, the TSA implemented a new rule requiring travelers coming from overseas to turn on their electronic devices, including phones, to prove they're actually functioning. If the device does not have power, you might be subjected to additional screening. This is for the safety of all passengers because phones can be used as detonators, jamming devices or to store bomb components. 

You already need to place large electronics, like a laptop or tablet, in a separate bin to go through the scanner. And though it likely doesn't happen too often, an agent might ask you to power something on, including your phone. If the device turns on, this is all the TSA agent should need to see and you can move forward. This confirms that the device hasn't been tampered with to be used for another purpose beyond its intended one.

CBP has different rules

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If an officer were to engage in a lengthier search without reasonable suspicion, this is where things get murky. Technically, border agents can run a manual search of your phone. These searches have been deemed by the Fourth Circuit as routine and a reasonable action under the Fourth Amendment, which is what protects you against unreasonable search and seizure without a warrant.

For international travelers, US Customs and Border Protection (CBP) can ask to look through your phone since this falls under the border search exception. CBP can detain your phone for what is considered to be a "brief, reasonable time" if they feel the need to conduct a routine inspection, per the CBP Directive. But without a warrant or reasonable suspicion, they can only do a basic inspection, where they look at things like text messages and app activity. With reasonable suspicion, they can do a thorough inspection, which involves downloading the contents onto another device. 

A proposal from late 2025 even aims to allow CBP to request five-year social media history from travelers entering from certain regions before they are permitted into the US, though this remains a proposal and is not actually law yet.

Keep your phone powered up

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Given that both TSA and border agents can ask you to power on your phone, you'll want to make sure your electronics don't die when you travel. Place your phone in the security bin, and if you're asked to turn it on, power the device up or light up the screen and unlock it to show that it's a functioning phone.

All that said, most travelers will never experience this. Provided your phone's battery is powered up, there shouldn't be any issues. But if you are asked to turn the phone on, TSA agents are well within their rights to require that you do so. If you're traveling internationally, you could run into murkier situations with CBP. But as far as TSA goes, all they want to know is that the phone isn't a dummy device being used for another reason and really is a working mobile phone.