how to save iphone call history to icloud

The iCloud backup does not save the call history. The call history remains on your iPhone and only the last 100 entries or so. The feature that you are asking about is not available on the iPhone.

Furthermore, You can suggest this feature directly to Apple by leaving a product feedback here 👉 Product Feedback - Apple 

Axel F.

You’re welcome.

One alternative to consider based on your specific needs:

While “Recents” only displays 100 calls, your phone is actually capable of storing more.

Unfortunately the only way to see the older calls is to delete the newer calls; “pulling-up” the newer calls into the “recents” display.

This might be ok for the very occasional “look back” but as it erases the more recent history (possibly needed in the future); it clearly has a significant shortcoming if data retention is important.

Using your carrier’s detailed-call records is the far more reliable and non “data destroying” method.

Some additional background:

iCloud iPhone backup does not “RE-backup” items which are already stored off-device by other means. (e.g. iCloud Photos, iCloud Messages, eMail, … etc.)

Detailed calling logs - generally saved by, and available from, your carrier - follow the same basic construct.

See more at:

What does iCloud back up? - Apple Support