Which devices support Siri AI?
Hardware is the first gate. Software, language and account region still matter.
iPhone and iPad
Apple’s support page lists iPhone 15 Pro models, iPhone 16 models or later, iPhone Duo and iPhone Air on iOS 27. The standard iPhone 15 is not in that list. For iPadOS 27, it lists iPad mini (A17 Pro) and iPad models with M1 or later. Check Settings → General → About for your exact model; a product family name can hide different chips.
Mac, Watch and Vision Pro
For macOS 27 Golden Gate, Apple lists Mac with M1 or later and MacBook Neo (A18 Pro). Apple Vision Pro requires visionOS 27. Apple Watch requires watchOS 27 on Series 9 or later, Ultra 2 or later, or SE 3, paired with an Apple Intelligence-enabled iPhone with Siri AI enabled. A watch cannot bypass the paired iPhone requirement.
Not all features share the same requirements
The base Siri AI hardware list does not guarantee every advanced feature. Apple documents stricter hardware and memory requirements for expressive voices, which are English-only. Use the live Apple support page to check a new model or a specific feature instead of assuming that a higher model number is sufficient.