diff --git a/hcloud/action_test.go b/hcloud/action_test.go
index 113019ea..275ea5b4 100644
--- a/hcloud/action_test.go
+++ b/hcloud/action_test.go
@@ -322,6 +322,7 @@ func TestResourceActionClientAll(t *testing.T) {
 }
 
 func TestActionClientWatchOverallProgress(t *testing.T) {
+	t.Parallel()
 	env := newTestEnv()
 	defer env.Teardown()
 
diff --git a/hcloud/client.go b/hcloud/client.go
index 570066ac..5558e3c6 100644
--- a/hcloud/client.go
+++ b/hcloud/client.go
@@ -377,6 +377,10 @@ func errorFromResponse(resp *Response, body []byte) error {
 	return hcErr
 }
 
+const (
+	headerCorrelationID = "X-Correlation-Id"
+)
+
 // Response represents a response from the API. It embeds http.Response.
 type Response struct {
 	*http.Response
@@ -410,6 +414,12 @@ func (r *Response) readMeta(body []byte) error {
 	return nil
 }
 
+// internalCorrelationID returns the unique ID of the request as set by the API. This ID can help with support requests,
+// as it allows the people working on identify this request in particular.
+func (r *Response) internalCorrelationID() string {
+	return r.Header.Get(headerCorrelationID)
+}
+
 // Meta represents meta information included in an API response.
 type Meta struct {
 	Pagination *Pagination
diff --git a/hcloud/error.go b/hcloud/error.go
index 2b5c4930..7403e420 100644
--- a/hcloud/error.go
+++ b/hcloud/error.go
@@ -100,6 +100,13 @@ type Error struct {
 }
 
 func (e Error) Error() string {
+	if resp := e.Response(); resp != nil {
+		correlationID := resp.internalCorrelationID()
+		if correlationID != "" {
+			// For easier debugging, the error string contains the Correlation ID of the response.
+			return fmt.Sprintf("%s (%s) (Correlation ID: %s)", e.Message, e.Code, correlationID)
+		}
+	}
 	return fmt.Sprintf("%s (%s)", e.Message, e.Code)
 }
 
diff --git a/hcloud/error_test.go b/hcloud/error_test.go
index 300added..c4816110 100644
--- a/hcloud/error_test.go
+++ b/hcloud/error_test.go
@@ -2,6 +2,7 @@ package hcloud
 
 import (
 	"fmt"
+	"net/http"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -27,6 +28,38 @@ func TestError_Error(t *testing.T) {
 			},
 			want: "unable to authenticate (unauthorized)",
 		},
+		{
+			name: "internal server error with correlation id",
+			fields: fields{
+				Code:    ErrorCodeUnknownError,
+				Message: "Creating image failed because of an unknown error.",
+				response: &Response{
+					Response: &http.Response{
+						StatusCode: http.StatusInternalServerError,
+						Header: func() http.Header {
+							headers := http.Header{}
+							// [http.Header] requires normalized header names, easiest to do by using the Set method
+							headers.Set("X-Correlation-ID", "foobar")
+							return headers
+						}(),
+					},
+				},
+			},
+			want: "Creating image failed because of an unknown error. (unknown_error) (Correlation ID: foobar)",
+		},
+		{
+			name: "internal server error without correlation id",
+			fields: fields{
+				Code:    ErrorCodeUnknownError,
+				Message: "Creating image failed because of an unknown error.",
+				response: &Response{
+					Response: &http.Response{
+						StatusCode: http.StatusInternalServerError,
+					},
+				},
+			},
+			want: "Creating image failed because of an unknown error. (unknown_error)",
+		},
 	}
 
 	for _, tt := range tests {