An electrostatic discharge (ESD) protection circuit includes a first diode, a second diode and an ESD clamp circuit. The first diode is in a semiconductor wafer, and is coupled to an input output (IO) pad. The second diode is in the semiconductor wafer, and is coupled to the first diode and the TO pad. The ESD clamp circuit is in the semiconductor wafer, and is coupled to the first diode and the second diode. The ESD clamp circuit includes a first signal tap region in the semiconductor wafer. The first signal tap region is coupled to a first voltage supply. The first diode is coupled to and configured to share the first signal tap region with the ESD clamp circuit.