After misplacing my phone for roughly 24 hours and then happily reuniting with it, I have learned a few lessons about securing an iPhone ($930 at Amazon). These tips will not only help keep your data safe during the uneasy time you and your iPhone are separated, but they will also help you track down your lost iPhone. Let's get to it.
1. Use a passcode
First step: set up a passcode. Do not walk around with an iPhone that anyone can swipe to open. Protect your iPhone with a passcode -- preferably a six-digit passcode or a custom numeric or alphanumeric code. With either Touch ID or, you won't need to enter your passcode unless your finger is wet or you are bundled up to a degree that your face is obscured. You can set up a passcode by going to Settings > Touch ID & Passcode or Settings > Face ID & Passcode and enroll your fingerprint or face. Make sure iPhone Unlock is toggled on after you set up your passcode.
2. Disable lock screen options
Even if you have a rock-solid passcode, a nefarious individual can still get into your phone via the lock screen. In her efforts to be helpful, Siri can share too much information from the lock screen, freely displaying personal information to whomever finds your lost phone. If this thought scares you, then it's best to disable Siri from the lock screen.
Another way hackers can get into your iPhone -- or at least buy some time to find a way to circumvent your passcode -- is to enable Airplane mode via Control Center from the lock screen. With your iPhone in Airplane mode, you can't track it via Find my iPhone.
To disable access to Siri and the Control Center from the lock screen, go to Settings > Touch ID & Passcode (or Face ID & Passcode) and toggle off Control Center and Siri in the Allow Access When Locked list.
3. Make your iPhone lock sooner
If you leave your iPhone behind in a restaurant, bus or another public place, someone could act quickly and get into your phone before your passcode is required. You can set your passcode to be required after a certain amount of time has passed since you last unlocked your phone so that you aren't constantly being asked to punch in your passcode each time you attempt to get into your phone. You can set it for up to four hours, which is on the convenient end of the convenience vs. security spectrum.
This setting can be found on the Touch ID & Passcode page of Settings. The most secure option is to set Require Passcode to Immediately, which will require you or anyone who picks up your phone to enter your passcode no matter how long ago you last unlocked your phone. This setting is set to Immediately by default when you set up Touch ID or Face ID.
4. Enable data protection
If someone has your iPhone and enough time, they could systematically guess at your passcode until they landed on the right combination, especially if you use only a four-digit passcode. To prevent a thief with tons of free time from accomplishing such a feat, your iPhone has a security feature that will wipe your phone if 10 consecutive incorrect attempts are made to enter your passcode. Don't worry: Your clumsy attempts at remembering your passcode -- or your kid's -- won't erase your phone. After the first four attempts, iOS adds a delay until you can try again. There's a one-minute delay after the fifth attempt, five minutes after the sixth, 15 minutes after attempts seven and eight, and a full hour after the ninth attempt.
Head to Settings > Touch ID & Passcode, scroll down to the bottom and toggle on Erase Data to enable this feature.
5. Turn on Find My iPhone
Even if you have ignored the first four steps here, I implore you to enable Find My iPhone. It doesn't add any inconvenience in the day-to-day operation of your iPhone and is easy to set up. With it enabled, you can track your lost device from another iOS device or your computer, seeing where your iPhone is on a map. You can also play sound on your lost phone to aid your search efforts. And if you really aren't having any luck with locating your iPhone, Find My iPhone lets you lock your iPhone and also remotely erase its data.
To turn on Find My iPhone, go to Settings > [your account name] > iCloud > Find My iPhone and toggle the switch on for Find My iPhone.
6. Set up two-step verification
For this last tip, I'll turn it over to Jason Cipriani, who previously wrote about how to enable set up two-step verification for your Apple ID. Two-step verification protects the data you have stored with Apple, including photos and files in iCloud and payment information for iTunes. With two-step verification enabled, someone would need another of your devices to get into your account, even if they had managed to get a hold of your password.
Originally published December 8, 2015. Updated June 8, 2018: Added information about data protection.