diff --git a/pkg/downloader/manager.go b/pkg/downloader/manager.go
index 348c78edb..094d9aff6 100644
--- a/pkg/downloader/manager.go
+++ b/pkg/downloader/manager.go
@@ -271,11 +271,11 @@ func (m *Manager) downloadAll(deps []*chart.Dependency) error {
 	var saveError error
 	churls := make(map[string]struct{})
 	for _, dep := range deps {
+		chartPath := filepath.Join(destPath, dep.Name)
 		// No repository means the chart is in charts directory
 		if dep.Repository == "" {
 			fmt.Fprintf(m.Out, "Dependency %s did not declare a repository. Assuming it exists in the charts directory\n", dep.Name)
 			// NOTE: we are only validating the local dependency conforms to the constraints. No copying to tmpPath is necessary.
-			chartPath := filepath.Join(destPath, dep.Name)
 			ch, err := loader.LoadDir(chartPath)
 			if err != nil {
 				return fmt.Errorf("unable to load chart '%s': %v", chartPath, err)
@@ -297,6 +297,13 @@ func (m *Manager) downloadAll(deps []*chart.Dependency) error {
 			}
 			continue
 		}
+
+		// Check if subchart already exist before downloading tarball.
+		// https://github.com/helm/helm/issues/30710
+		if _, err := os.Stat(chartPath); !os.IsNotExist(err) {
+			return fmt.Errorf("dependency conflict detected: A subchart named '%s' already exists in charts/ directory", dep.Name)
+		}
+
 		if strings.HasPrefix(dep.Repository, "file://") {
 			if m.Debug {
 				fmt.Fprintf(m.Out, "Archiving %s from repo %s\n", dep.Name, dep.Repository)
diff --git a/pkg/downloader/manager_test.go b/pkg/downloader/manager_test.go
index 53955c45b..c565cb3ac 100644
--- a/pkg/downloader/manager_test.go
+++ b/pkg/downloader/manager_test.go
@@ -298,6 +298,24 @@ version: 0.1.0`
 	if err == nil {
 		t.Fatal("Expected error for bad dependency name")
 	}
+
+	remoteDep := &chart.Dependency{
+		Name:       "sub",
+		Repository: "oci://remote",
+		Version:    "0.0.1",
+	}
+
+	// create a 'tmpcharts' directory to test #30710
+	if err := os.MkdirAll(filepath.Join(chartPath, "charts", "sub"), 0755); err != nil {
+		t.Fatal(err)
+	}
+	err = m.downloadAll([]*chart.Dependency{remoteDep})
+	if err == nil {
+		t.Fatal("Expected error as subchart already exist")
+	}
+	if err.Error() != "dependency conflict detected: A subchart named 'sub' already exists in charts/ directory" {
+		t.Fatal("Download should failed with conflict issue")
+	}
 }
 
 func TestUpdateBeforeBuild(t *testing.T) {