diff --git a/siwe/__init__.py b/siwe/__init__.py
index be432f0..a9721e0 100644
--- a/siwe/__init__.py
+++ b/siwe/__init__.py
@@ -5,6 +5,7 @@
     DomainMismatch,
     ExpiredMessage,
     InvalidSignature,
+    ISO8601Datetime,
     MalformedSession,
     NonceMismatch,
     NotYetValidMessage,