diff --git a/rust/test/BUILD b/rust/test/BUILD
index 5b5e216fa8..decb41a187 100644
--- a/rust/test/BUILD
+++ b/rust/test/BUILD
@@ -74,7 +74,7 @@ rust_proto_library(
     name = "unittest_proto3_optional_rust_proto",
     testonly = True,
     visibility = [
-        "//rust/test/shared:__subpackages__",
+        "//visibility:private",  # Only private by automation, not intent. Owner may accept CLs adding visibility. See go/scheuklappen#explicit-private.
     ],
     deps = [
         UNITTEST_PROTO3_OPTIONAL_TARGET,
@@ -84,20 +84,14 @@ rust_proto_library(
 rust_cc_proto_library(
     name = "unittest_proto3_optional_cc_rust_proto",
     testonly = True,
-    visibility = [
-        "//rust/test/cpp:__subpackages__",
-        "//rust/test/shared:__subpackages__",
-    ],
+    visibility = ["//rust/test/shared:__subpackages__"],
     deps = [UNITTEST_PROTO3_OPTIONAL_CC_TARGET],
 )
 
 rust_upb_proto_library(
     name = "unittest_proto3_optional_upb_rust_proto",
     testonly = True,
-    visibility = [
-        "//rust/test/cpp:__subpackages__",
-        "//rust/test/shared:__subpackages__",
-    ],
+    visibility = ["//rust/test/shared:__subpackages__"],
     deps = [UNITTEST_PROTO3_OPTIONAL_TARGET],
 )