Samsung
Turn Bluetooth On or Off auf Samsung
Bluetooth on a Samsung phone works as a background radio that keeps scanning for paired accessories, such as a car system, headphones, or a smart speaker. As soon as one of those devices comes into range, the phone reconnects automatically, even without opening any app.
To reach the control, tap Settings ➔ Connections, then use the switch next to Bluetooth to enable or disable it. Turning the switch off stops all scanning and ends any active connection right away.
Leaving Bluetooth on with nothing paired only uses a small amount of battery on current Samsung chipsets. Switching it off matters more when you want to stop one specific automatic reconnection, for example a car you no longer want triggering hands-free mode, or a speaker in a shared room.
If Bluetooth turns back on by itself after you disable it, check whether a companion app for connected earbuds or a watch is forcing it on through its own background service. In that case, turn off the auto-reconnect option inside that app instead of relying on the system switch alone.