One way to do it (might be the same as @thefury) is: Configure one of the I2S as slave then share the clock signal. The GPIO trick can be referred to from components/esp_driver_i2s/test_apps/i2s/main/test_i2s.c: i2s_test_io_config . After I2S finishes initializing GPIO, use esp_rom_gpio_connect_out_...