diff --git a/examples/bluetooth/bluedroid/classic_bt/a2dp_sink_stream/README.md b/examples/bluetooth/bluedroid/classic_bt/a2dp_sink_stream/README.md
index 65eed2e5d41..9285e4cb760 100644
--- a/examples/bluetooth/bluedroid/classic_bt/a2dp_sink_stream/README.md
+++ b/examples/bluetooth/bluedroid/classic_bt/a2dp_sink_stream/README.md
@@ -50,7 +50,15 @@ If the internal DAC is selected, analog audio will be available on GPIO25 and GP
 
 #### ESP32-S31
 
-The default output is idle. If I2S is used, it can be configured through menuconfig. Currently, DAC is not supported.
+The default output is I2S. If I2S is used, it can be configured through menuconfig. The default I2S connections are shown below:
+
+| ESP pin   | I2S signal   |
+| :-------- | :----------- |
+| GPIO3     | LRCK         |
+| GPIO4     | DATA         |
+| GPIO2     | BCK          |
+
+Currently, DAC is not supported.
 
 ### Configure the project
 
diff --git a/examples/bluetooth/bluedroid/classic_bt/a2dp_sink_stream/sdkconfig.defaults.esp32s31 b/examples/bluetooth/bluedroid/classic_bt/a2dp_sink_stream/sdkconfig.defaults.esp32s31
index 9a77739a3d4..76b30b33b95 100644
--- a/examples/bluetooth/bluedroid/classic_bt/a2dp_sink_stream/sdkconfig.defaults.esp32s31
+++ b/examples/bluetooth/bluedroid/classic_bt/a2dp_sink_stream/sdkconfig.defaults.esp32s31
@@ -1,2 +1,5 @@
 CONFIG_PARTITION_TABLE_SINGLE_APP_LARGE=y
-CONFIG_EXAMPLE_A2DP_SINK_OUTPUT_IDLE=y
+CONFIG_EXAMPLE_A2DP_SINK_OUTPUT_EXTERNAL_I2S=y
+CONFIG_EXAMPLE_I2S_BCK_PIN=2
+CONFIG_EXAMPLE_I2S_LRCK_PIN=3
+CONFIG_EXAMPLE_I2S_DATA_PIN=4
diff --git a/examples/bluetooth/bluedroid/classic_bt/a2dp_sink_stream_aac/README.md b/examples/bluetooth/bluedroid/classic_bt/a2dp_sink_stream_aac/README.md
index 5089aa70461..b7677198539 100644
--- a/examples/bluetooth/bluedroid/classic_bt/a2dp_sink_stream_aac/README.md
+++ b/examples/bluetooth/bluedroid/classic_bt/a2dp_sink_stream_aac/README.md
@@ -39,7 +39,15 @@ If the internal DAC is selected, analog audio will be available on GPIO25 and GP
 
 #### ESP32-S31
 
-The default output is idle. If I2S is used, it can be configured through menuconfig. Currently, DAC is not supported.
+The default output is I2S. If I2S is used, it can be configured through menuconfig. The default I2S connections are shown below:
+
+| ESP pin   | I2S signal   |
+| :-------- | :----------- |
+| GPIO3     | LRCK         |
+| GPIO4     | DATA         |
+| GPIO2     | BCK          |
+
+Currently, DAC is not supported.
 
 ### Configure the project
 
diff --git a/examples/bluetooth/bluedroid/classic_bt/a2dp_sink_stream_aac/sdkconfig.defaults.esp32s31 b/examples/bluetooth/bluedroid/classic_bt/a2dp_sink_stream_aac/sdkconfig.defaults.esp32s31
index 9a77739a3d4..76b30b33b95 100644
--- a/examples/bluetooth/bluedroid/classic_bt/a2dp_sink_stream_aac/sdkconfig.defaults.esp32s31
+++ b/examples/bluetooth/bluedroid/classic_bt/a2dp_sink_stream_aac/sdkconfig.defaults.esp32s31
@@ -1,2 +1,5 @@
 CONFIG_PARTITION_TABLE_SINGLE_APP_LARGE=y
-CONFIG_EXAMPLE_A2DP_SINK_OUTPUT_IDLE=y
+CONFIG_EXAMPLE_A2DP_SINK_OUTPUT_EXTERNAL_I2S=y
+CONFIG_EXAMPLE_I2S_BCK_PIN=2
+CONFIG_EXAMPLE_I2S_LRCK_PIN=3
+CONFIG_EXAMPLE_I2S_DATA_PIN=4