Bluetooth Tether is a free Android app that enables automatic Bluetooth tethering when Bluetooth turns on, usually after a reboot or when exiting airplane mode. With this app, users can easily share their phone's internet connection with other devices without having to manually enable tethering every time.

It should be noted that this app uses internal APIs, which means that it may not work on all phones. It has only been tested on various Nexus phones. Additionally, some carriers may prevent Bluetooth tethering altogether, and this app cannot help in such cases. Nevertheless, Bluetooth Tether offers a convenient solution for those who frequently use Bluetooth tethering and want to automate the process.

Overall, Bluetooth Tether is a useful utility app for Android users who want to streamline their Bluetooth tethering experience.