how to disable the date and time for my child phone?

I have also followed these instruction and my daughter can still change the date and time in the phone so it defeats the purpose of screen time if they can adjust it at will.

This doesn’t work.

Hello help_required_now,

Welcome to Apple Support Communities. 

We understand that you want to prevent your child from changing the date and time, so that they can bypass restrictions set. We are happy to help.

You can restrict Date & Time by going to Settings > Screen Time > Content & Privacy Settings > Location Services > Enter Screen Time Passcode > Scroll to the bottom to System Services > Setting Time Zone and disable that. Once complete, we'd recommend pressing Back > Scroll to the top of the page and select Don't Allow Changes. Once complete, this should make Date & Time appear greyed out and unaccessible. Your child will still be able to change the time from 12-hour setting to 24-hour setting, but unable to change the Time Zone setting.

Here’s more on what else you can restrict: Use parental controls on your child's iPhone, iPad, and iPod touch - Apple Support

"Here are the things you can restrict:

• Location Services: Lock the settings to allow apps and websites to use location
• Contacts: Prevent apps from accessing your Contacts
• Calendars: Prevent apps from accessing your Calendar
• Reminders: Prevent apps from accessing your Reminders
• Photos: Prevent apps from requesting access to your photos
• Share My Location: Lock the settings for location sharing in Messages and Find My Friends
• Bluetooth sharing: Prevent devices and apps from sharing data through Bluetooth
• Microphone: Prevent apps from requesting access to your microphone
• Speech Recognition: Prevent apps from accessing Speech Recognition or Dictation
• Apple Advertising: Prevent changes to advertising settings
• Allow Apps to Request to Track: Prevent tracking activity by apps that you've denied access to
• Media & Apple Music: Prevent apps from accessing your photos, videos, or music library"

Let us know if you have further questions.

Take care.

I have followed these instructions but they have not worked. It is still possible for the time & timezone to be overridden which means my child is able to (& does) bypass the screen time locks I have in place on his iPad.

I did all the steps, including “location services>don’t allow changes” and even though it appears grey in System services>setting time zone it does not appear like that when going to general>date & time.

help!! My daughter is bypassing screen time settings by doint that every single time… I’m sure I’m not the only one!

Update: It works....but with a catch. It seems like to prevent someone from just turning Setting Time Zone back on again, I have to select "Don't Allow Changes" to Location Services as a whole. This means I can't change ANY location settings (including granting apps permission to use location) after I do this.

Huge pain in the *** but then again, that's Screen Time for you. After some messing around with it, Screen Time (at least for now) seems full-proof but with a lot tinkering & workarounds. 

Works for me! Thanks.

iPhone 12 Pro Max, iOS 17.5.1

Take the phone away from her. If she must have a way to communicate, buy a cheap dumb phone for her.