The most reliable source is the SonicEDIT.ROM - EYX (Official) Android Port on Game Jolt. This page typically hosts the "Tails Demo" or legacy versions of the port.
Sites like AppsGeyser also host community builds, though users should always exercise caution when downloading files from non-developer-run mirrors. Key Features of the Android Port i--- Sonic.eyx Download Android
Since Sonic.eyx is a fan-made project and not an official SEGA release, it is not available on the Google Play Store. You must download the APK from community-driven platforms. The most reliable source is the SonicEDIT
Other developers like Maniayt have released versions such as SONIC.EXE: Sonic.eyx Android Port on Game Jolt. i--- Sonic.eyx Download Android