For Siri to work offline, your iPhone must download a local database that allows it to recognize your voice and process commands directly on the A12 Bionic chip (or newer) rather than sending them to a server. This download typically happens automatically in the background when connected to Wi-Fi. How to Fix the "Siri Not Available" Error
If your iPhone is failing to download this data, follow these steps to trigger the process: How To Use Siri Offline on iPhone or iPad For Siri to work offline, your iPhone must
Since the release of iOS 15, Apple has enabled on-device speech processing, allowing Siri to handle many requests without an internet connection. However, if you see the message it means your device has not yet downloaded the necessary speech models and language files required for offline functionality. Why Siri Requires This Download However, if you see the message it means