diff --git a/substrate/primitives/core/src/offchain/mod.rs b/substrate/primitives/core/src/offchain/mod.rs
index 4ffadc3e40..3f0eed87a3 100644
--- a/substrate/primitives/core/src/offchain/mod.rs
+++ b/substrate/primitives/core/src/offchain/mod.rs
@@ -208,12 +208,14 @@ impl OpaqueMultiaddr {
 #[derive(
 	Clone, Copy, PartialEq, Eq, Ord, PartialOrd, Default, RuntimeDebug, PassByInner, Encode, Decode,
 )]
+#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
 pub struct Timestamp(u64);
 
 /// Duration type
 #[derive(
 	Clone, Copy, PartialEq, Eq, Ord, PartialOrd, Default, RuntimeDebug, PassByInner, Encode, Decode,
 )]
+#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
 pub struct Duration(u64);
 
 impl Duration {