diff --git a/hikaricp-common/src/main/java/com/zaxxer/hikari/proxy/ConnectionProxy.java b/hikaricp-common/src/main/java/com/zaxxer/hikari/proxy/ConnectionProxy.java
index c9e598e3..1f8fab6d 100644
--- a/hikaricp-common/src/main/java/com/zaxxer/hikari/proxy/ConnectionProxy.java
+++ b/hikaricp-common/src/main/java/com/zaxxer/hikari/proxy/ConnectionProxy.java
@@ -207,6 +207,13 @@ public abstract class ConnectionProxy implements IHikariConnectionProxy
       }
    }
 
+   /** {@inheritDoc} */
+   @Override
+   public boolean isClosed() throws SQLException
+   {
+      return (delegate == ClosedConnection.CLOSED_CONNECTION);
+   }
+
    /** {@inheritDoc} */
    @Override
    public Statement createStatement() throws SQLException