diff --git a/src/ipv4.rs b/src/ipv4.rs
index b738ac4..0f6d033 100644
--- a/src/ipv4.rs
+++ b/src/ipv4.rs
@@ -449,4 +449,16 @@ mod test {
         let expected = Ipv4Network::new(Ipv4Addr::new(127, 0, 0, 1), 32).unwrap();
         assert_eq!(net, expected);
     }
+
+    #[test]
+    fn test_send() {
+        fn assert_send<T: Send>() {}
+        assert_send::<Ipv4Network>();
+    }
+
+    #[test]
+    fn test_sync() {
+        fn assert_sync<T: Sync>() {}
+        assert_sync::<Ipv4Network>();
+    }
 }
diff --git a/src/ipv6.rs b/src/ipv6.rs
index 640a28f..0cb859e 100644
--- a/src/ipv6.rs
+++ b/src/ipv6.rs
@@ -389,4 +389,16 @@ mod test {
         let expected = Ipv6Network::new(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1), 128).unwrap();
         assert_eq!(net, expected);
     }
+
+    #[test]
+    fn test_send() {
+        fn assert_send<T: Send>() {}
+        assert_send::<Ipv6Network>();
+    }
+
+    #[test]
+    fn test_sync() {
+        fn assert_sync<T: Sync>() {}
+        assert_sync::<Ipv6Network>();
+    }
 }