No, you do not have to turn off the M1 Wireless Mouse while charging. The M1 Wireless Mouse keeps working while charging, but turning it off gives a more efficient charge.

• Charge with the included USB-C cable.
• The blue LED shows charging status and turns off when the mouse is fully charged.
• The M1 Wireless Mouse still connects by Bluetooth while charging. The USB-C cable does not provide a wired connection.