diff --git a/src/corelib/time/qtimezoneprivate.cpp b/src/corelib/time/qtimezoneprivate.cpp
index 71b1674b846..33770b0f2d4 100644
--- a/src/corelib/time/qtimezoneprivate.cpp
+++ b/src/corelib/time/qtimezoneprivate.cpp
@@ -465,7 +465,8 @@ QByteArray QTimeZonePrivate::systemTimeZoneId() const
 
 bool QTimeZonePrivate::isTimeZoneIdAvailable(const QByteArray& ianaId) const
 {
-    // Fall-back implementation, can be made faster in subclasses
+    // Fall-back implementation, can be made faster in subclasses.
+    // Backends that don't cache the available list SHOULD override this.
     const QList<QByteArray> tzIds = availableTimeZoneIds();
     return std::binary_search(tzIds.begin(), tzIds.end(), ianaId);
 }
diff --git a/src/corelib/time/qtimezoneprivate_android.cpp b/src/corelib/time/qtimezoneprivate_android.cpp
index 05b4bd8cbc1..0194352f5ea 100644
--- a/src/corelib/time/qtimezoneprivate_android.cpp
+++ b/src/corelib/time/qtimezoneprivate_android.cpp
@@ -206,6 +206,12 @@ QByteArray QAndroidTimeZonePrivate::systemTimeZoneId() const
     return id.toString().toUtf8();
 }
 
+bool QAndroidTimeZonePrivate::isTimeZoneIdAvailable(const QByteArray &ianaId) const
+{
+    QAndroidTimeZonePrivate probe(ianaId);
+    return probe.isValid();
+}
+
 QList<QByteArray> QAndroidTimeZonePrivate::availableTimeZoneIds() const
 {
     QList<QByteArray> availableTimeZoneIdList;
diff --git a/src/corelib/time/qtimezoneprivate_p.h b/src/corelib/time/qtimezoneprivate_p.h
index 4942ecd477a..f04157a654c 100644
--- a/src/corelib/time/qtimezoneprivate_p.h
+++ b/src/corelib/time/qtimezoneprivate_p.h
@@ -463,7 +463,7 @@ public:
     Data data(qint64 forMSecsSinceEpoch) const override;
 
     QByteArray systemTimeZoneId() const override;
-
+    bool isTimeZoneIdAvailable(const QByteArray &ianaId) const override;
     QList<QByteArray> availableTimeZoneIds() const override;
 
 private: