diff --git a/lib/cylc/cycling/loader.py b/lib/cylc/cycling/loader.py
index 1b912c006cd..07142ddaebc 100755
--- a/lib/cylc/cycling/loader.py
+++ b/lib/cylc/cycling/loader.py
@@ -23,7 +23,7 @@
 
 import integer
 import iso8601
-from isodatetime.date import Calendar
+from isodatetime.data import Calendar
 
 
 ISO8601_CYCLING_TYPE = 'iso8601'