diff --git a/components/esp_modem/include/esp_modem_c_api_types.h b/components/esp_modem/include/esp_modem_c_api_types.h
index 577b4ce03..2c37b796b 100644
--- a/components/esp_modem/include/esp_modem_c_api_types.h
+++ b/components/esp_modem/include/esp_modem_c_api_types.h
@@ -39,6 +39,7 @@ typedef enum esp_modem_dce_mode
 {
     ESP_MODEM_MODE_COMMAND,  /**< Default mode after modem startup, used for sending AT commands */
     ESP_MODEM_MODE_DATA,     /**< Used for switching to PPP mode for the modem to connect to a network */
+    ESP_MODEM_MODE_CMUX,     /**< Multiplexed terminal mode */
 } esp_modem_dce_mode_t;
 
 /**
diff --git a/components/esp_modem/src/esp_modem_c_api.cpp b/components/esp_modem/src/esp_modem_c_api.cpp
index 6f5a6ad7f..e89fc1950 100644
--- a/components/esp_modem/src/esp_modem_c_api.cpp
+++ b/components/esp_modem/src/esp_modem_c_api.cpp
@@ -125,6 +125,13 @@ extern "C" esp_err_t esp_modem_set_mode(esp_modem_dce_t *dce_wrap, esp_modem_dce
         dce_wrap->dce->set_data();
     } else if (mode == ESP_MODEM_MODE_COMMAND) {
         dce_wrap->dce->exit_data();
+    } else if (mode == ESP_MODEM_MODE_CMUX) {
+        if (dce_wrap->dce->set_mode(modem_mode::CMUX_MODE) &&
+            // automatically switch to data mode for the primary terminal
+            dce_wrap->dce->set_mode(modem_mode::DATA_MODE)) {
+            return ESP_OK;
+        }
+        return ESP_FAIL;
     } else {
         return ESP_ERR_NOT_SUPPORTED;
     }