How can I use siri when I’m offline?

On some, but not all devices, Siri will work offline for many commands.

Note: iPhone needs to download Siri speech models before it can process requests on-device. To check if your device uses on-device processing, go to Settings > Siri & Search. If the text below Siri & Dictation History reads “Voice input is processed on iPhone,” the Siri speech models have been downloaded.

Use Siri on iPhone - Apple Support

Some but not all Siri requests require the iPhone to be connected to the internet.

Use Siri on iPhone - Apple Support