diff --git a/msim/src/sim/runtime/mod.rs b/msim/src/sim/runtime/mod.rs
index c1bf436..e7a1168 100644
--- a/msim/src/sim/runtime/mod.rs
+++ b/msim/src/sim/runtime/mod.rs
@@ -457,8 +457,8 @@ impl NodeHandle {
     /// Spawn a future onto the runtime.
     pub fn spawn<F>(&self, future: F) -> JoinHandle<F::Output>
     where
-        F: Future + Send + 'static,
-        F::Output: Send + 'static,
+        F: Future + 'static,
+        F::Output: 'static,
     {
         self.task.spawn(future)
     }
diff --git a/msim/src/sim/task.rs b/msim/src/sim/task.rs
index 84d6593..e24c1e1 100644
--- a/msim/src/sim/task.rs
+++ b/msim/src/sim/task.rs
@@ -453,8 +453,8 @@ impl TaskNodeHandle {
 
     pub fn spawn<F>(&self, future: F) -> JoinHandle<F::Output>
     where
-        F: Future + Send + 'static,
-        F::Output: Send + 'static,
+        F: Future + 'static,
+        F::Output: 'static,
     {
         self.spawn_local(future)
     }