diff --git a/src/libstd/io/mod.rs b/src/libstd/io/mod.rs
index 83c492fecf9745d0c936d339b73b3b93ee3df62c..88d556229e4cb98ca2a1763199800dd21440b6e2 100644
--- a/src/libstd/io/mod.rs
+++ b/src/libstd/io/mod.rs
@@ -951,6 +951,12 @@ fn take(self, limit: u64) -> Take<Self>
 #[repr(transparent)]
 pub struct IoSliceMut<'a>(sys::io::IoSliceMut<'a>);
 
+#[stable(feature = "iovec-send-sync", since = "1.44.0")]
+unsafe impl<'a> Send for IoSliceMut<'a> {}
+
+#[stable(feature = "iovec-send-sync", since = "1.44.0")]
+unsafe impl<'a> Sync for IoSliceMut<'a> {}
+
 #[stable(feature = "iovec", since = "1.36.0")]
 impl<'a> fmt::Debug for IoSliceMut<'a> {
     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
@@ -1054,6 +1060,12 @@ fn deref_mut(&mut self) -> &mut [u8] {
 #[repr(transparent)]
 pub struct IoSlice<'a>(sys::io::IoSlice<'a>);
 
+#[stable(feature = "iovec-send-sync", since = "1.44.0")]
+unsafe impl<'a> Send for IoSlice<'a> {}
+
+#[stable(feature = "iovec-send-sync", since = "1.44.0")]
+unsafe impl<'a> Sync for IoSlice<'a> {}
+
 #[stable(feature = "iovec", since = "1.36.0")]
 impl<'a> fmt::Debug for IoSlice<'a> {
     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {