How to Fix Slow Cellular Data on iPhone 12 Pro after iOS 18 update?

I have full bars of 5G reception. When the internet does load, it's extremely slow for a few minutes then it hangs again for up to 15 minutes. I've restarted my phone several times, removed the sim, reset network settings but it didn’t help. Going on 48 hours now of not being able to use cellular data on my phone. No issues at all before update to iOS18. Anyone else having the same issue?


[Re-Titled by Moderator]

iPhone 12 Pro, iOS 18

Posted on Sep 18, 2024 4:03 PM

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Question marked as Top-ranking reply

Posted on Dec 8, 2024 9:07 PM

I have an update. I got ahold of the carrier and explained what happened. Not sure what they did, but after 5-6 minutes of wait they told me to put the phone in a plane mode for 1 minute and then test the speed. Whatever they did worked and I have a good internet speed ever since.


if you chose to do a network reset, keep in mind that all of your WiFi passwords will be erased. Considering it didn’t fix my issues as I now have to get all of the WiFi passwords that I’ve been keeping for years.


[Edited by Moderator]

21 replies
Question marked as Top-ranking reply

Dec 8, 2024 9:07 PM in response to Anna Dorofeeva

I have an update. I got ahold of the carrier and explained what happened. Not sure what they did, but after 5-6 minutes of wait they told me to put the phone in a plane mode for 1 minute and then test the speed. Whatever they did worked and I have a good internet speed ever since.


if you chose to do a network reset, keep in mind that all of your WiFi passwords will be erased. Considering it didn’t fix my issues as I now have to get all of the WiFi passwords that I’ve been keeping for years.


[Edited by Moderator]

Sep 24, 2024 2:34 AM in response to Tom_Hertz

If you're experiencing slow cellular data on your iPhone 12 Pro after the iOS 18 update, despite full 5G bars, try these steps: update carrier settings, toggle Airplane mode, and check for any pending iOS updates. If the issue persists, contact your carrier for network troubleshooting or visit an Apple store for further diagnostics. Several users have reported similar problems after the update.

Sep 24, 2024 1:05 PM in response to Tom_Hertz

I have the same issue. I have a new iPhone 16 Pro Max and I'm on IOS 18.1 Beta 5. My phone shows that I'm on the 5G ultra wide network, but my downloads are abysmal - typically under 5Mbs. WIFI is fine, but cellular (both at home and at work) are terribly slow, so slow that I cannot update Apps from the App Store. I spoke with my carrier (Visible) and they tried a few things, but nothing has helped. I have toggled Airplane mode, Reset Network Settings, rebooted several times. The last suggestion from Visible was a factory reset. I might be doing that tonight.

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How to Fix Slow Cellular Data on iPhone 12 Pro after iOS 18 update?

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