diff --git a/src/corelib/text/qstring.cpp b/src/corelib/text/qstring.cpp
index 33a54ab2e1..bc1cdd343c 100644
--- a/src/corelib/text/qstring.cpp
+++ b/src/corelib/text/qstring.cpp
@@ -5413,6 +5413,15 @@ QByteArray QString::toLatin1_helper_inplace(QString &s)
     return QByteArray(std::move(ba_d));
 }
 
+// QLatin1 methods that use helpers from qstring.cpp
+char16_t *QLatin1::convertToUnicode(char16_t *out, QLatin1StringView in) noexcept
+{
+    const qsizetype len = in.size();
+    qt_from_latin1(out, in.data(), len);
+    return std::next(out, len);
+}
+
+
 /*!
     \fn QByteArray QString::toLatin1() const
 
diff --git a/src/corelib/text/qstringconverter.cpp b/src/corelib/text/qstringconverter.cpp
index 035f08b784..e25a2c7756 100644
--- a/src/corelib/text/qstringconverter.cpp
+++ b/src/corelib/text/qstringconverter.cpp
@@ -1527,19 +1527,7 @@ static char *toUtf32LE(char *out, QStringView in, QStringConverter::State *state
     return QUtf32::convertFromUnicode(out, in, state, LittleEndianness);
 }
 
-void qt_from_latin1(char16_t *dst, const char *str, size_t size) noexcept;
-
-static QChar *fromLatin1(QChar *out, QByteArrayView in, QStringConverter::State *state)
-{
-    Q_ASSERT(state);
-    Q_UNUSED(state);
-
-    qt_from_latin1(reinterpret_cast<char16_t *>(out), in.data(), size_t(in.size()));
-    return out + in.size();
-}
-
-
-static char *toLatin1(char *out, QStringView in, QStringConverter::State *state)
+char *QLatin1::convertFromUnicode(char *out, QStringView in, QStringConverter::State *state) noexcept
 {
     Q_ASSERT(state);
     if (state->flags & QStringConverter::Flag::Stateless) // temporary
@@ -1725,7 +1713,7 @@ const QStringConverter::Interface QStringConverter::encodingInterfaces[QStringCo
     { "UTF-32", fromUtf32, fromUtf32Len, toUtf32, toUtf32Len },
     { "UTF-32LE", fromUtf32LE, fromUtf32Len, toUtf32LE, toUtf32Len },
     { "UTF-32BE", fromUtf32BE, fromUtf32Len, toUtf32BE, toUtf32Len },
-    { "ISO-8859-1", fromLatin1, fromLatin1Len, toLatin1, toLatin1Len },
+    { "ISO-8859-1", QLatin1::convertToUnicode, fromLatin1Len, QLatin1::convertFromUnicode, toLatin1Len },
     { "Locale", fromLocal8Bit, fromUtf8Len, toLocal8Bit, toUtf8Len }
 };
 
diff --git a/src/corelib/text/qstringconverter_p.h b/src/corelib/text/qstringconverter_p.h
index ce0ee3096c..1864ec7693 100644
--- a/src/corelib/text/qstringconverter_p.h
+++ b/src/corelib/text/qstringconverter_p.h
@@ -29,6 +29,29 @@ enum qchar8_t : uchar {};
 using qchar8_t = char8_t;
 #endif
 
+struct QLatin1
+{
+    // Defined in qstring.cpp
+    static char16_t *convertToUnicode(char16_t *dst, QLatin1StringView in) noexcept;
+
+    static QChar *convertToUnicode(QChar *buffer, QLatin1StringView in) noexcept
+    {
+        char16_t *dst = reinterpret_cast<char16_t *>(buffer);
+        dst = convertToUnicode(dst, in);
+        return reinterpret_cast<QChar *>(dst);
+    }
+
+    static QChar *convertToUnicode(QChar *dst, QByteArrayView in,
+                                   [[maybe_unused]] QStringConverterBase::State *state) noexcept
+    {
+        Q_ASSERT(state);
+
+        return convertToUnicode(dst, QLatin1StringView(in.data(), in.size()));
+    }
+
+    static char *convertFromUnicode(char *out, QStringView in, QStringConverter::State *state) noexcept;
+};
+
 struct QUtf8BaseTraits
 {
     static const bool isTrusted = false;
diff --git a/tests/auto/corelib/text/qstringconverter/tst_qstringconverter.cpp b/tests/auto/corelib/text/qstringconverter/tst_qstringconverter.cpp
index a60478d542..2156b40fb6 100644
--- a/tests/auto/corelib/text/qstringconverter/tst_qstringconverter.cpp
+++ b/tests/auto/corelib/text/qstringconverter/tst_qstringconverter.cpp
@@ -134,6 +134,8 @@ private slots:
 
     void convertL1U8();
 
+    void convertL1U16();
+
 #if QT_CONFIG(icu)
     void roundtripIcu_data();
     void roundtripIcu();
@@ -353,6 +355,33 @@ void tst_QStringConverter::convertUtf8CharByChar()
     QCOMPARE(reencoded, ba);
 }
 
+void tst_QStringConverter::convertL1U16()
+{
+    const QLatin1StringView latin1("some plain latin1 text");
+    const QString qstr(latin1);
+
+    QStringDecoder decoder(QStringConverter::Latin1);
+    QVERIFY(decoder.isValid());
+    QString uniString = decoder(latin1);
+    QCOMPARE(uniString, qstr);
+    QCOMPARE(latin1, uniString.toLatin1());
+
+    // do it again (using .decode())
+    uniString = decoder.decode(latin1);
+    QCOMPARE(uniString, qstr);
+    QCOMPARE(latin1, uniString.toLatin1());
+
+    QStringEncoder encoder(QStringConverter::Latin1);
+    QByteArray reencoded = encoder(uniString);
+    QCOMPARE(reencoded, QByteArrayView(latin1));
+    QCOMPARE(reencoded, uniString.toLatin1());
+
+    // do it again (using .encode())
+    reencoded = encoder.encode(uniString);
+    QCOMPARE(reencoded, QByteArrayView(latin1));
+    QCOMPARE(reencoded, uniString.toLatin1());
+}
+
 void tst_QStringConverter::roundtrip_data()
 {
     QTest::addColumn<QStringView>("utf16");