diff --git a/crates/conversions/src/felt252.rs b/crates/conversions/src/felt252.rs
index 8295cdbd4c..e9b4208b68 100644
--- a/crates/conversions/src/felt252.rs
+++ b/crates/conversions/src/felt252.rs
@@ -130,8 +130,12 @@ pub trait SerializeAsFelt252Vec: Sized {
 }
 
 impl SerializeAsFelt252Vec for Vec<Felt252> {
-    fn serialize_as_felt252_vec(&self) -> Vec<Felt252> {
-        self.to_owned()
+    fn serialize_as_felt252(self, output: &mut Vec<Felt252>) {
+        output.extend(self);
+    }
+
+    fn serialize_as_felt252_vec(self) -> Vec<Felt252> {
+        self
     }
 }