diff --git a/src/corelib/global/qlibraryinfo.cpp b/src/corelib/global/qlibraryinfo.cpp
index 4b116c54b2e..da39f1eb6c2 100644
--- a/src/corelib/global/qlibraryinfo.cpp
+++ b/src/corelib/global/qlibraryinfo.cpp
@@ -62,14 +62,14 @@ QLibrarySettings::QLibrarySettings() : paths(false), reloadOnQAppAvailable(false
 
 QSettings *QLibrarySettings::configuration()
 {
-    if (reloadOnQAppAvailable && QCoreApplication::instance() != nullptr)
+    if (reloadOnQAppAvailable && QCoreApplication::instanceExists())
         load();
     return settings.get();
 }
 
 bool QLibrarySettings::havePaths()
 {
-    if (reloadOnQAppAvailable && QCoreApplication::instance() != nullptr)
+    if (reloadOnQAppAvailable && QCoreApplication::instanceExists())
         load();
     return paths;
 }
@@ -78,7 +78,7 @@ void QLibrarySettings::load()
 {
     // If we get any settings here, those won't change when the application shows up.
     settings = findConfiguration();
-    reloadOnQAppAvailable = !settings && !QCoreApplication::instance();
+    reloadOnQAppAvailable = !settings && !QCoreApplication::instanceExists();
 
     if (settings) {
         // This code needs to be in the regular library, as otherwise a qt.conf that
@@ -121,7 +121,7 @@ static std::unique_ptr<QSettings> findConfiguration()
         }
     }
 #endif
-    if (QCoreApplication::instance()) {
+    if (QCoreApplication::instanceExists()) {
         QString pwd = QCoreApplication::applicationDirPath();
         qtconfig = pwd + u"/qt" QT_STRINGIFY(QT_VERSION_MAJOR) ".conf"_s;
         if (QFile::exists(qtconfig))
@@ -270,7 +270,7 @@ QVersionNumber QLibraryInfo::version() noexcept
 
 static QString prefixFromAppDirHelper()
 {
-    if (QCoreApplication::instance()) {
+    if (QCoreApplication::instanceExists()) {
 #ifdef Q_OS_DARWIN
         CFBundleRef bundleRef = CFBundleGetMainBundle();
         if (bundleRef) {
diff --git a/src/corelib/kernel/qcoreapplication.cpp b/src/corelib/kernel/qcoreapplication.cpp
index 93ecf12b758..5008ed579dd 100644
--- a/src/corelib/kernel/qcoreapplication.cpp
+++ b/src/corelib/kernel/qcoreapplication.cpp
@@ -144,6 +144,21 @@ Q_CONSTINIT QCoreApplication *QCoreApplication::self = nullptr;
 Q_CONSTINIT static QBasicAtomicPointer<QCoreApplication> g_self = nullptr;
 #  undef qApp
 #  define qApp g_self.loadRelaxed()
+
+/*!
+    \internal
+
+    This function is a Qt 6 thread-safe (no data races) version of:
+    \code
+        QCoreApplication::instance() != nullptr
+    \endcode
+
+    We may remove it in Qt 7.0 because the above will be thread-safe.
+*/
+bool QCoreApplication::instanceExists() noexcept
+{
+    return qApp != nullptr;
+}
 #endif
 
 #if !defined(Q_OS_WIN) || defined(QT_BOOTSTRAPPED)
@@ -276,7 +291,7 @@ void qAddPreRoutine(QtStartUpFunction p)
         return;
 
     if (preRoutinesCalled) {
-        Q_ASSERT(QCoreApplication::instance());
+        Q_ASSERT(qApp);
         p();
     }
 
@@ -467,11 +482,6 @@ QCoreApplicationPrivate::~QCoreApplicationPrivate()
 #endif
 }
 
-bool QCoreApplicationPrivate::isAlive() noexcept
-{
-    return qApp != nullptr;
-}
-
 #ifndef QT_NO_QOBJECT
 
 void QCoreApplicationPrivate::cleanupThreadData()
diff --git a/src/corelib/kernel/qcoreapplication.h b/src/corelib/kernel/qcoreapplication.h
index 87e78035d60..ac9de4db5e7 100644
--- a/src/corelib/kernel/qcoreapplication.h
+++ b/src/corelib/kernel/qcoreapplication.h
@@ -96,8 +96,10 @@ public:
 
 #if QT_VERSION >= QT_VERSION_CHECK(7, 0, 0)
     static QCoreApplication *instance() noexcept { return self.loadRelaxed(); }
+    static bool instanceExists() noexcept { return instance() != nullptr; }
 #else
     static QCoreApplication *instance() noexcept { return self; }
+    static bool instanceExists() noexcept;
 #endif
 
 #ifndef QT_NO_QOBJECT
diff --git a/src/corelib/kernel/qcoreapplication_p.h b/src/corelib/kernel/qcoreapplication_p.h
index 021f1a25387..98a5af29167 100644
--- a/src/corelib/kernel/qcoreapplication_p.h
+++ b/src/corelib/kernel/qcoreapplication_p.h
@@ -61,7 +61,6 @@ public:
 #endif
     ~QCoreApplicationPrivate();
 
-    static bool isAlive() noexcept;
     void init();
 
     QString appName() const;
diff --git a/src/corelib/kernel/qcoreevent.cpp b/src/corelib/kernel/qcoreevent.cpp
index d638e3524ca..8b6e7c83262 100644
--- a/src/corelib/kernel/qcoreevent.cpp
+++ b/src/corelib/kernel/qcoreevent.cpp
@@ -329,7 +329,7 @@ QEvent::QEvent(Type type)
 
 QEvent::~QEvent()
 {
-    if (m_posted && QCoreApplication::instance())
+    if (m_posted && QCoreApplication::instanceExists())
         QCoreApplicationPrivate::removePostedEvent(this);
 }
 
diff --git a/src/corelib/kernel/qeventloop.cpp b/src/corelib/kernel/qeventloop.cpp
index c02afd172dc..a07589addb6 100644
--- a/src/corelib/kernel/qeventloop.cpp
+++ b/src/corelib/kernel/qeventloop.cpp
@@ -68,7 +68,7 @@ QEventLoop::QEventLoop(QObject *parent)
 {
     Q_D(QEventLoop);
     QThreadData *threadData = d->threadData.loadRelaxed();
-    if (!QCoreApplication::instance() && threadData->requiresCoreApplication) {
+    if (!QCoreApplication::instanceExists() && threadData->requiresCoreApplication) {
         qWarning("QEventLoop: Cannot be used without QCoreApplication");
     } else {
         threadData->ensureEventDispatcher();
diff --git a/src/corelib/kernel/qtranslator.cpp b/src/corelib/kernel/qtranslator.cpp
index 713c029c347..fe7d0b2f21e 100644
--- a/src/corelib/kernel/qtranslator.cpp
+++ b/src/corelib/kernel/qtranslator.cpp
@@ -397,7 +397,7 @@ QTranslator::QTranslator(QObject * parent)
 
 QTranslator::~QTranslator()
 {
-    if (QCoreApplication::instance())
+    if (QCoreApplication::instanceExists())
         QCoreApplication::removeTranslator(this);
     Q_D(QTranslator);
     d->clear();
diff --git a/src/corelib/thread/qthreadstorage.cpp b/src/corelib/thread/qthreadstorage.cpp
index 3b2d4f5c9ca..0deff1b19d9 100644
--- a/src/corelib/thread/qthreadstorage.cpp
+++ b/src/corelib/thread/qthreadstorage.cpp
@@ -157,7 +157,7 @@ void QThreadStorageData::finish(void **p)
         locker.unlock();
 
         if (!destructor) {
-            if (QCoreApplicationPrivate::isAlive())
+            if (QCoreApplication::instanceExists())
                 qWarning("QThreadStorage: entry %d destroyed before end of thread %p",
                          i, QThread::currentThread());
             continue;
diff --git a/src/dbus/qdbusintegrator.cpp b/src/dbus/qdbusintegrator.cpp
index 534999378d5..bdd49464b50 100644
--- a/src/dbus/qdbusintegrator.cpp
+++ b/src/dbus/qdbusintegrator.cpp
@@ -559,7 +559,7 @@ bool QDBusConnectionPrivate::handleMessage(const QDBusMessage &amsg)
         // run it through the spy filters (if any) before the regular processing:
         // a) if it's a local message, we're in the caller's thread, so invoke the filter directly
         // b) if it's an external message, post to the main thread
-        if (Q_UNLIKELY(qDBusSpyHookList.exists()) && qApp) {
+        if (Q_UNLIKELY(qDBusSpyHookList.exists()) && QCoreApplication::instanceExists()) {
             if (isLocal) {
                 Q_ASSERT(QThread::currentThread() != thread());
                 qDBusDebug() << this << "invoking message spies directly";
diff --git a/src/gui/image/qpixmap.cpp b/src/gui/image/qpixmap.cpp
index cbfb5e2d8d4..a0ba3ccef51 100644
--- a/src/gui/image/qpixmap.cpp
+++ b/src/gui/image/qpixmap.cpp
@@ -48,7 +48,7 @@ QT_WARNING_DISABLE_MSVC(4723)
 
 static bool qt_pixmap_thread_test()
 {
-    if (Q_UNLIKELY(!QCoreApplication::instance())) {
+    if (!QCoreApplication::instanceExists()) {
         qFatal("QPixmap: Must construct a QGuiApplication before a QPixmap");
         return false;
     }
diff --git a/src/network/kernel/qdnslookup.cpp b/src/network/kernel/qdnslookup.cpp
index 182540c37f2..9151eb84e4f 100644
--- a/src/network/kernel/qdnslookup.cpp
+++ b/src/network/kernel/qdnslookup.cpp
@@ -776,7 +776,7 @@ void QDnsLookup::lookup()
     Q_D(QDnsLookup);
     d->isFinished = false;
     d->reply = QDnsLookupReply();
-    if (!QCoreApplication::instance()) {
+    if (!QCoreApplication::instanceExists()) {
         // NOT qCWarning because this isn't a result of the lookup
         qWarning("QDnsLookup requires a QCoreApplication");
         return;
diff --git a/src/sql/kernel/qsqldatabase.cpp b/src/sql/kernel/qsqldatabase.cpp
index bb7d5a1ea53..70840010555 100644
--- a/src/sql/kernel/qsqldatabase.cpp
+++ b/src/sql/kernel/qsqldatabase.cpp
@@ -23,12 +23,12 @@ Q_STATIC_LOGGING_CATEGORY(lcSqlDb, "qt.sql.qsqldatabase")
 using namespace Qt::StringLiterals;
 
 #define CHECK_QCOREAPPLICATION \
-    if (Q_UNLIKELY(!QCoreApplication::instance())) { \
+    if (Q_UNLIKELY(!QCoreApplication::instanceExists())) { \
         qCWarning(lcSqlDb, "QSqlDatabase requires a QCoreApplication"); \
         return; \
     }
 #define CHECK_QCOREAPPLICATION_RETVAL \
-    if (Q_UNLIKELY(!QCoreApplication::instance())) { \
+    if (Q_UNLIKELY(!QCoreApplication::instanceExists())) { \
         qCWarning(lcSqlDb, "QSqlDatabase requires a QCoreApplication"); \
         return {}; \
     }
@@ -661,7 +661,7 @@ void QSqlDatabasePrivate::init(const QString &type)
         qCWarning(lcSqlDb, "QSqlDatabase: %ls driver not loaded", qUtf16Printable(type));
         qCWarning(lcSqlDb, "QSqlDatabase: available drivers: %ls",
                   qUtf16Printable(QSqlDatabase::drivers().join(u' ')));
-        if (QCoreApplication::instance() == nullptr)
+        if (!QCoreApplication::instanceExists())
             qCWarning(lcSqlDb, "QSqlDatabase: an instance of QCoreApplication is required for loading driver plugins");
         driver = shared_null()->driver;
     }