Apple to Let iPhones in Japan Replace Siri with Third-Party Assistants via the Side Button in iOS 26.2

Apple has quietly introduced a noteworthy change in the iOS 26.2 beta that could reshape how the Side Button functions on iPhones but, for now, only in Japan. According to a new post on Apple’s Developer blog (reported by 9to5Mac), iPhone users in Japan may soon be able to reassign a press-and-hold on the Side Button to launch third-party voice assistants, instead of defaulting to Siri.

What’s Changing And How It Works

• SystemVoiceAssistant: Code discovered in iOS 26.2 beta 3 reveals a system app called “SystemVoiceAssistant,” suggesting that Apple is building in support to change which voice assistant the Side Button activates.
• New Settings: Strings in the beta reference options like “Assign a voice-enabled app to the Side Button” and “Select Another Default Side Button App.”
• App Intents Framework: To support this, Apple is leveraging its App Intents system. Developers who want their conversational voice apps to be Side Button–activated must:
  1. Include a special entitlement (com.apple.developer.side-button-access.allow) in their app project.
  2. Create an app intent using the activate schema to handle the launch.
  3. Immediately start an audio session when the app is launched, to meet user expectations of instant voice interaction.

Limited to Japan For Now

This new functionality won’t be available globally at least at first. According to Apple’s documentation:

• To use a third-party assistant from the Side Button, the Apple ID must be registered to Japan, and the iPhone must be physically located in Japan.
• Apple’s blog makes it clear this support is region-locked: “In Japan, people might place an action … that instantly launches your voice-based conversational app.”

Why Japan First? Regulatory Pressure

The timing aligns with regulatory changes in Japan. The Mobile Software Competition Act, which goes into effect in December 2025, requires major platform owners like Apple to give third-party developers access to system-level features including voice assistant access.
Because of this, Apple’s addition of Side Button reassignability appears to be a compliance measure rather than a purely user-driven feature expansion.

Implications for Users in Japan

• More Choice: Once live, iPhone users in Japan could use assistants like Google Gemini, Amazon Alexa, or other third-party conversational apps when they long-press the Side Button.
• Instant Launch Experience: Developers are encouraged to make sure their apps respond instantly (e.g., starting an audio session right away), to mimic the responsiveness users expect from Siri.
• Developer Adoption Matters: For this to be meaningful, third-party apps must explicitly support this feature by implementing the required entitlement and app intent.

There’s speculation that this feature could expand beyond Japan in the future:

• Apple may replicate similar functionality in EU markets, driven by the Digital Markets Act (DMA), which demands “interoperability” for core services like voice assistants.
• But for now, Apple’s documentation and code signal that iOS 26.2 will offer this flexibility only in Japan.

With iOS 26.2, Apple is enabling iPhones in Japan to replace Siri as the Side Button assistant, allowing third-party voice apps to be launched instead. The change, likely prompted by new local competition laws, marks a significant shift in how Apple balances platform control and regulatory compliance even if the feature is limited for now.