diff --git a/library/alloc/src/string.rs b/library/alloc/src/string.rs
index b1513e5e0f31c..b3f0bc6baac49 100644
--- a/library/alloc/src/string.rs
+++ b/library/alloc/src/string.rs
@@ -2701,7 +2701,8 @@ impl<'a> From<Cow<'a, str>> for String {
 
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> From<&'a str> for Cow<'a, str> {
+#[rustc_const_unstable(feature = "const_convert", issue = "88674")]
+impl<'a> const From<&'a str> for Cow<'a, str> {
     /// Converts a string slice into a [`Borrowed`] variant.
     /// No heap allocation is performed, and the string
     /// is not copied.
@@ -2722,7 +2723,8 @@ impl<'a> From<&'a str> for Cow<'a, str> {
 
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> From<String> for Cow<'a, str> {
+#[rustc_const_unstable(feature = "const_convert", issue = "88674")]
+impl<'a> const From<String> for Cow<'a, str> {
     /// Converts a [`String`] into an [`Owned`] variant.
     /// No heap allocation is performed, and the string
     /// is not copied.