If iPhone is locked with a passcode, you may still be able to make an emergency call.
On the Enter Passcode screen, tap Emergency Call, then dial the number using the keypad.
IMPORTANT: Only emergency numbers valid in the region where you’re making the call will work. In some countries, you can’t make emergency calls unless your SIM card is installed and activated, and the SIM PIN has been correctly entered or turned off.
In the U.S., location information (if available) is provided to emergency service providers when you dial 911.
IMPORTANT: You should not rely on wireless devices for essential communications, such as medical emergencies. Use of any cellular phone to call emergency services may not work in all locations. Emergency numbers and services vary by region, and sometimes an emergency call cannot be placed due to network availability or environmental interference. Some cellular networks may not accept an emergency call from iPhone if it doesn’t have a SIM, if you locked your SIM, or if you haven’t activated your iPhone.