diff --git a/node-graph/libraries/core-types/src/runtime.rs b/node-graph/libraries/core-types/src/runtime.rs
index f206045753..b0163fa2b3 100644
--- a/node-graph/libraries/core-types/src/runtime.rs
+++ b/node-graph/libraries/core-types/src/runtime.rs
@@ -22,6 +22,13 @@ pub trait Runtime {
 #[derive(Clone)]
 pub struct RuntimeHandle(pub Arc<DynRuntime>);
 
+// SAFETY: wasm is single threaded, so the handle never actually crosses a thread.
+#[cfg(target_family = "wasm")]
+unsafe impl Send for RuntimeHandle {}
+// SAFETY: as in Send.
+#[cfg(target_family = "wasm")]
+unsafe impl Sync for RuntimeHandle {}
+
 impl std::fmt::Debug for RuntimeHandle {
 	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 		f.debug_struct("RuntimeHandle").finish_non_exhaustive()
@@ -70,6 +77,13 @@ pub struct GraphRuntime<S> {
 	spawner: S,
 }
 
+// SAFETY: wasm is single threaded, so the runtime never actually crosses a thread.
+#[cfg(target_family = "wasm")]
+unsafe impl<S> Send for GraphRuntime<S> {}
+// SAFETY: as in Send.
+#[cfg(target_family = "wasm")]
+unsafe impl<S> Sync for GraphRuntime<S> {}
+
 impl<S> GraphRuntime<S> {
 	pub fn new(spawner: S) -> Self {
 		Self {