diff --git a/namespace/id.go b/namespace/id.go
index f2ddc7bd..d5dd8e77 100644
--- a/namespace/id.go
+++ b/namespace/id.go
@@ -1,6 +1,9 @@
 package namespace
 
-import "bytes"
+import (
+	"bytes"
+	"encoding/hex"
+)
 
 type ID []byte
 
@@ -28,3 +31,8 @@ func (nid ID) Size() IDSize {
 func (nid ID) String() string {
 	return string(nid)
 }
+
+// HexString returns hexadecimal encoding of nid.
+func (nid ID) HexString() string {
+	return hex.EncodeToString(nid)
+}
diff --git a/namespace/id_test.go b/namespace/id_test.go
new file mode 100644
index 00000000..15919b66
--- /dev/null
+++ b/namespace/id_test.go
@@ -0,0 +1,12 @@
+package namespace
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestID_HexString(t *testing.T) {
+	nID := ID("12345678")
+	require.Equal(t, "3132333435363738", nID.HexString())
+}