iCloud Photos keeps photos and videos up to date across Apple devices. When Wi-Fi is unavailable, an iPhone or iPad with a cellular data plan can sync the library over mobile data when cellular use is enabled for Photos.
Cellular syncing needs an active mobile internet connection and enough available iCloud storage. With neither Wi-Fi nor usable mobile data, new photos stay on the device until it reconnects. Uploads and downloads count against your data plan, and a large library or videos can cause additional charges.
iCloud Photos synchronizes library changes, including deletions, across devices using the same Apple Account. It is separate from an iCloud device backup, and photos already in iCloud Photos are not duplicated in that backup. Cellular permission allows syncing away from Wi-Fi, but power, network and storage conditions can still pause it.
The settings paths apply to iOS 27 and iPadOS 27 on an iPhone or a Wi-Fi + Cellular iPad with an active data plan. Depending on the device and region, Cellular may be labeled Cellular Data, Mobile Data or Mobile Service.
Steps to sync iCloud Photos over cellular data on iPhone and iPad:
- Open Settings > [your name] > iCloud > Photos.
- Turn on Sync this iPhone or Sync this iPad if it is off.
On iOS 27 and iPadOS 27, the optional Sync Immediately > For Today setting here prioritizes newly added library items for one day. It can increase cellular data use and still pauses in Low Data Mode or Low Power Mode.
- Open Settings > Cellular.
If Cellular Data is off, turn it on before enabling cellular access for Photos.
- Turn on the Photos switch in the cellular app list.
If Photos is not visible, tap Show All to expand the list. The Photos switch permits mobile data use when Wi-Fi is unavailable. Turning it off restricts Photos to Wi-Fi.
- Turn off Wi-Fi in Settings > Wi-Fi for a cellular-only upload test.
Wi-Fi can be turned back on after the test. Keeping it off until upload completion makes the test specific to cellular data.
- Open a new webpage in Safari over the cellular connection.
A page that cannot load indicates a connectivity problem rather than proof that Photos is restricted to Wi-Fi.
- Take one test photo with Camera.
A still photo keeps the test smaller than a video, although other pending library items can also upload once cellular use is allowed.
- Tap the profile button in the upper corner of Photos > Collections.
The library status below your name and photo count shows whether Photos is syncing or paused, along with the last sync time. A photo visible only in the local library or an increase in cellular data usage does not prove upload completion.
If syncing is paused, Low Data Mode and Low Power Mode messages indicate reduced data or battery use; their switches are in Settings. Low Data Mode is under the cellular line's data options, with a Data Mode submenu on 5G; Low Power Mode is under Battery, with Power Mode on supported iPhones. A low battery needs charging, an overheated device needs time to cool, and full iCloud storage needs space freed or a larger plan. For temporary power, performance or connection pauses, Sync Now may be available. Apple's Photos sync-status guidance explains the messages. Turning iCloud Photos off is not a remedy for a paused upload.
- Wait for the library status to show that syncing has finished while Wi-Fi remains off.
The last sync time should be later than the test photo. An uploading indicator or a paused message means the upload test is not yet complete; allowing cellular data does not guarantee immediate uploads.
- Confirm that the test photo appears in Photos on iCloud.com or another device using the same Apple Account.
The receiving browser or device also needs internet access. The new photo appearing there, after a completed sync with Wi-Fi off on the source device, confirms that the photo reached iCloud over cellular data.