diff --git a/.changeset/perfect-jeans-search.md b/.changeset/perfect-jeans-search.md
new file mode 100644
index 000000000..923e2dc0f
--- /dev/null
+++ b/.changeset/perfect-jeans-search.md
@@ -0,0 +1,5 @@
+---
+"@lion/ui": patch
+---
+
+fix(ui/calendar): use correct firstUpdated type signature
diff --git a/packages/ui/components/calendar/src/LionCalendar.js b/packages/ui/components/calendar/src/LionCalendar.js
index 4627a2b48..885e6e7d9 100644
--- a/packages/ui/components/calendar/src/LionCalendar.js
+++ b/packages/ui/components/calendar/src/LionCalendar.js
@@ -300,7 +300,9 @@ export class LionCalendar extends LocalizeMixin(LitElement) {
     }
   }
 
-  firstUpdated() {
+  /** @param {import('lit').PropertyValues } changedProperties */
+  firstUpdated(changedProperties) {
+    super.firstUpdated(changedProperties);
     this.__calculateInitialCentralDate();
 
     // setup data for initial render