To turn off Dial Assist on an iPhone, open Settings, tap Apps, tap Phone, then scroll down and turn off Dial Assist. On older iOS versions that have no Apps section, go straight to Settings > Phone. With Dial Assist off, your iPhone stops working out international or local prefixes for you, so you dial or save the full number yourself.
What Dial Assist does
Apple describes Dial Assist in one line: it automatically determines the correct international or local prefix when dialing. A prefix is the group of digits in front of a phone number, such as the country code +1 for the United States or +44 for the United Kingdom.
Apple’s iOS 18 guide adds two details. The prefix is added when you call your contacts and favorites, and the setting is labeled as a GSM feature, so it depends on your carrier and network. That is why Dial Assist is most useful when you travel and call numbers that were saved at home without a country code.
Before you start
- Version: the steps below match Apple’s iPhone User Guide for iOS 18, iOS 26, and iOS 27, where app settings sit under Settings > Apps.
- What changes: only how outgoing phone calls are dialed. Your saved contacts are not edited.
- Cost: turning the setting off does not change what a call costs. Apple says to contact your carrier for international rates and other charges.
How to turn off Dial Assist on iPhone
If you often call home from abroad using contacts saved without a country code, read the next section before you switch this off. Those calls may stop connecting until you update the numbers.
- Open the Settings app, the gray gear icon on your Home Screen.
- Scroll down the main Settings screen and tap Apps.
- Tap Phone in the list of apps.
- Scroll down the Phone settings screen until you see Dial Assist.
- Tap the switch next to Dial Assist to turn it off.
There is no Save button. The change applies as soon as the switch moves. Apple lists the setting in Change your Phone settings on iPhone.
On older iOS versions
Older iOS versions do not have an Apps section in Settings. On those iPhones, open Settings, scroll down, and tap Phone directly. Dial Assist is near the bottom of that screen.
What to do after you turn it off
With Dial Assist off, plan on entering international numbers in full. The most reliable format starts with a plus sign and the country code, because that format does not depend on which country you are calling from.
Dial a full international number
- Open the Phone app and tap Keypad.
- Touch and hold the 0 key until + appears.
- Enter the country code, then the rest of the number.
- Tap the green call button.
Apple documents the plus sign shortcut in Make a call on iPhone. For keypad basics, see how to dial a number on an iPhone.
Update your saved contacts
Numbers you call often are easier to manage if the country code is saved with them. Open the contact, tap Edit, and retype the number starting with + and the country code. Our guide on how to edit a contact on iPhone walks through each field.
When turning off Dial Assist makes sense
- International calls fail or reach the wrong place, and your contacts already include full country codes.
- You use a calling card or a dial-around service that needs the exact digits you type.
- You want to rule out the setting while you troubleshoot a calling problem.
If you mostly make local calls and nothing is going wrong, you can leave the setting alone. Apple does not publish a list of situations where it should be off, so treat it as a troubleshooting step, not a required change.
How to check the setting and turn it back on
Go back to Settings > Apps > Phone and look at the Dial Assist switch. Gray means off and green means on. To undo the change, tap the switch again. Nothing else is reset, and your contacts and call history stay the same.
To confirm the result, place a call to a number that failed before. If the call still does not connect, the problem is probably not Dial Assist.
Troubleshooting
Dial Assist is missing
First, scroll all the way down the Phone settings screen, since the switch sits below the other call options. Then check that you are in Settings > Apps > Phone and not in the Phone app itself. Apple labels the feature as GSM, so it may not appear with every carrier or line. If it is still missing, your carrier can tell you whether it is supported on your plan.
International calls still fail
Apple’s call troubleshooting steps start with your carrier: confirm your account allows the call and that there is no outage or billing block. After that, Apple suggests checking for a carrier settings update and an iOS update, turning Airplane Mode on and off, and resetting network settings. See Apple’s If your call fails or you can’t receive calls on your iPhone for the full list.
Resetting network settings erases saved Wi-Fi passwords and VPN settings, so read what each iPhone reset option does before you use it.
Calls work at home but not abroad
That points to roaming or your plan, not to Dial Assist. Ask your carrier whether international calling and roaming are active on your line. If you travel with an older Verizon phone, see what International CDMA means on the iPhone.
Other Phone settings nearby
- Show My Caller ID: hides your number on outgoing calls. Apple notes that if you do not see it, your carrier may not allow you to turn off caller ID.
- Call Blocking & Identification: manages caller ID apps and their priority.
- Default Calling App: lets you pick a supported third-party app for making and receiving calls.
Frequently asked questions
Is Dial Assist on by default?
Apple’s guide does not state the default. Its instructions are written as “turn on Dial Assist,” so check the switch in Settings > Apps > Phone to see how your own iPhone is set.
Does turning off Dial Assist change my contacts?
No. The switch only controls whether your iPhone works out a prefix when a call is placed. Numbers saved in Contacts stay exactly as you entered them.
Does Dial Assist affect text messages?
Apple describes Dial Assist as a setting for dialing, and it lives in the Phone settings. Apple’s guide does not mention any effect on Messages.
Will turning off Dial Assist lower my international calling costs?
No. The setting changes how a number is dialed, not how it is billed. Rates come from your carrier, so check your plan before you call another country.
Do I need Dial Assist for local calls?
Usually not. If you are at home and calling local numbers, calls connect the same way for most people. The setting matters most when you are in another country or calling one.
Next step
Turn off Dial Assist, then call one number that failed before. If it connects, add + and the country code to the contacts you call most so they work from anywhere.
Matthew Burleigh is the founder, head writer, and editor of Solve Your Tech, which he launched in 2012. He has written technology tutorials since 2008 and worked in IT since 2003, including small-business support, IT management, and consulting. He holds Bachelor’s and Master’s degrees in Computer Science from Arizona State University.
Matthew writes practical guides for Windows, iPhone and iPad, Microsoft Office, Outlook, Google apps, and Android. Solve Your Tech’s guides are tested on current devices or checked against official product documentation, with clear steps, sources, and update dates.
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