WiFi - WiFi.macAddress()

WiFi.macAddress(mac);

#include <SPI.h>
#include <WiFi.h>

char ssid[] = "yourNetwork";     // the name of your network
int status = WL_IDLE_STATUS;     // the Wifi radio's status

byte mac[6];                     // the MAC address of your Wifi shield


void setup()
{
 Serial.begin(9600);

 status = WiFi.begin(ssid);

 if ( status != WL_CONNECTED) {
    Serial.println("Couldn't get a wifi connection");
    while(true);
  }
  // if you are connected, print your MAC address:
  else {
  WiFi.macAddress(mac);
  Serial.print("MAC: ");
  Serial.print(mac[5],HEX);
  Serial.print(":");
  Serial.print(mac[4],HEX);
  Serial.print(":");
  Serial.print(mac[3],HEX);
  Serial.print(":");
  Serial.print(mac[2],HEX);
  Serial.print(":");
  Serial.print(mac[1],HEX);
  Serial.print(":");
  Serial.println(mac[0],HEX);
  }
}

void loop () {}