diff --git a/java/fory-core/src/main/java/org/apache/fory/serializer/LocaleSerializer.java b/java/fory-core/src/main/java/org/apache/fory/serializer/LocaleSerializer.java
index 00ae9b0884..231684dffd 100644
--- a/java/fory-core/src/main/java/org/apache/fory/serializer/LocaleSerializer.java
+++ b/java/fory-core/src/main/java/org/apache/fory/serializer/LocaleSerializer.java
@@ -22,19 +22,17 @@
 import java.util.HashMap;
 import java.util.Locale;
 import java.util.Map;
-import org.apache.fory.collection.Tuple3;
 import org.apache.fory.config.Config;
 import org.apache.fory.context.ReadContext;
 import org.apache.fory.context.WriteContext;
 
-/** Local serializer for {@link Locale}. */
+/** Serializer for {@link Locale}. */
 public final class LocaleSerializer extends ImmutableSerializer<Locale> implements Shareable {
   // Using `new HashMap<>` to ensure thread safety by java constructor semantics.
-  private static final Map<Tuple3<String, String, String>, Locale> LOCALE_CACHE =
-      new HashMap<>(createCacheMap());
+  private static final Map<String, Locale> LOCALE_CACHE = new HashMap<>(createCacheMap());
 
-  static Map<Tuple3<String, String, String>, Locale> createCacheMap() {
-    Map<Tuple3<String, String, String>, Locale> map = new HashMap<>();
+  static Map<String, Locale> createCacheMap() {
+    Map<String, Locale> map = new HashMap<>();
     populateMap(map, Locale.US);
     populateMap(map, Locale.SIMPLIFIED_CHINESE);
     populateMap(map, Locale.CHINESE);
@@ -62,45 +60,26 @@ static Map<Tuple3<String, String, String>, Locale> createCacheMap() {
     return map;
   }
 
-  private static void populateMap(Map<Tuple3<String, String, String>, Locale> map, Locale locale) {
-    map.put(Tuple3.of(locale.getCountry(), locale.getLanguage(), locale.getVariant()), locale);
+  private static void populateMap(Map<String, Locale> map, Locale locale) {
+    map.put(locale.toLanguageTag(), locale);
   }
 
   public LocaleSerializer(Config config) {
     super(config, Locale.class);
   }
 
-  public void write(WriteContext writeContext, Locale l) {
-    writeContext.writeString(l.getLanguage());
-    writeContext.writeString(l.getCountry());
-    writeContext.writeString(l.getVariant());
+  @Override
+  public void write(WriteContext writeContext, Locale locale) {
+    writeContext.writeString(locale.toLanguageTag());
   }
 
+  @Override
   public Locale read(ReadContext readContext) {
-    String language = readContext.readString();
-    String country = readContext.readString();
-    String variant = readContext.readString();
-    // Fast path for Default/US/SIMPLIFIED_CHINESE
-    Locale defaultLocale = Locale.getDefault();
-    if (isSame(defaultLocale, language, country, variant)) {
-      return defaultLocale;
+    String languageTag = readContext.readString();
+    Locale locale = LOCALE_CACHE.get(languageTag);
+    if (locale != null) {
+      return locale;
     }
-    if (defaultLocale != Locale.US && isSame(Locale.US, language, country, variant)) {
-      return Locale.US;
-    }
-    if (isSame(Locale.SIMPLIFIED_CHINESE, language, country, variant)) {
-      return Locale.SIMPLIFIED_CHINESE;
-    }
-    Object o = LOCALE_CACHE.get(Tuple3.of(language, country, variant));
-    if (o != null) {
-      return (Locale) o;
-    }
-    return new Locale(language, country, variant);
-  }
-
-  static boolean isSame(Locale locale, String language, String country, String variant) {
-    return (locale.getLanguage().equals(language)
-        && locale.getCountry().equals(country)
-        && locale.getVariant().equals(variant));
+    return Locale.forLanguageTag(languageTag);
   }
 }
diff --git a/java/fory-core/src/test/java/org/apache/fory/serializer/LocaleSerializerTest.java b/java/fory-core/src/test/java/org/apache/fory/serializer/LocaleSerializerTest.java
index d53ddd118b..e899af23fd 100644
--- a/java/fory-core/src/test/java/org/apache/fory/serializer/LocaleSerializerTest.java
+++ b/java/fory-core/src/test/java/org/apache/fory/serializer/LocaleSerializerTest.java
@@ -41,6 +41,76 @@ public void testWrite() {
     serDeCheckSerializerAndEqual(fory, Locale.CHINA, "LocaleSerializer");
     serDeCheckSerializerAndEqual(fory, Locale.TAIWAN, "LocaleSerializer");
     serDeCheckSerializerAndEqual(fory, Locale.getDefault(), "LocaleSerializer");
+    serDeCheckSerializerAndEqual(fory, Locale.ROOT, "LocaleSerializer");
+    serDeCheckSerializerAndEqual(fory, Locale.GERMANY, "LocaleSerializer");
+    serDeCheckSerializerAndEqual(fory, Locale.FRANCE, "LocaleSerializer");
+
+    // Script preservation
+    Locale zhHans = Locale.forLanguageTag("zh-Hans-CN");
+    Locale zhHant = Locale.forLanguageTag("zh-Hant-TW");
+    Locale srLatn = Locale.forLanguageTag("sr-Latn-RS");
+    Locale srCyrl = Locale.forLanguageTag("sr-Cyrl-RS");
+    Locale uzLatn = Locale.forLanguageTag("uz-Latn-UZ");
+    serDeCheckSerializerAndEqual(fory, zhHans, "LocaleSerializer");
+    serDeCheckSerializerAndEqual(fory, zhHant, "LocaleSerializer");
+    serDeCheckSerializerAndEqual(fory, srLatn, "LocaleSerializer");
+    serDeCheckSerializerAndEqual(fory, srCyrl, "LocaleSerializer");
+    serDeCheckSerializerAndEqual(fory, uzLatn, "LocaleSerializer");
+
+    // Extension preservation
+    Locale thaiDigits =
+        new Locale.Builder().setLanguage("th").setRegion("TH").setExtension('u', "nu-thai").build();
+    Locale japaneseCal =
+        new Locale.Builder()
+            .setLanguage("ja")
+            .setRegion("JP")
+            .setExtension('u', "ca-japanese")
+            .build();
+    serDeCheckSerializerAndEqual(fory, thaiDigits, "LocaleSerializer");
+    serDeCheckSerializerAndEqual(fory, japaneseCal, "LocaleSerializer");
+
+    // Script + Extension preservation
+    Locale scriptAndExt =
+        new Locale.Builder()
+            .setLanguage("zh")
+            .setScript("Hans")
+            .setRegion("CN")
+            .setExtension('u', "nu-native")
+            .build();
+    serDeCheckSerializerAndEqual(fory, scriptAndExt, "LocaleSerializer");
+
+    // Variants
+    serDeCheckSerializerAndEqual(fory, new Locale("en", "US", "POSIX"), "LocaleSerializer");
+    serDeCheckSerializerAndEqual(fory, new Locale("en", "US", "WIN"), "LocaleSerializer");
+    serDeCheckSerializerAndEqual(fory, new Locale("ja", "JP", "JP"), "LocaleSerializer");
+    serDeCheckSerializerAndEqual(fory, new Locale("th", "TH", "TH"), "LocaleSerializer");
+
+    // Cache hit singleton check
+    org.testng.Assert.assertSame(fory.deserialize(fory.serialize(Locale.US)), Locale.US);
+    org.testng.Assert.assertSame(fory.deserialize(fory.serialize(Locale.GERMANY)), Locale.GERMANY);
+    org.testng.Assert.assertSame(fory.deserialize(fory.serialize(Locale.FRANCE)), Locale.FRANCE);
+    org.testng.Assert.assertSame(fory.deserialize(fory.serialize(Locale.ROOT)), Locale.ROOT);
+  }
+
+  @Test
+  public void testAvailableLocales() {
+    Fory fory =
+        Fory.builder()
+            .withXlang(false)
+            .requireClassRegistration(false)
+            .withCompatible(false)
+            .build();
+    for (Locale locale : Locale.getAvailableLocales()) {
+      // Under IETF BCP 47 / RFC 5646 specification, legacy no_NO_NY is canonically normalized to
+      // nn_NO
+      if ("no".equals(locale.getLanguage())
+          && "NO".equals(locale.getCountry())
+          && "NY".equals(locale.getVariant())) {
+        continue;
+      }
+      Locale deserialized = (Locale) fory.deserialize(fory.serialize(locale));
+      org.testng.Assert.assertEquals(deserialized, locale);
+    }
   }
 
   @Test(dataProvider = "foryCopyConfig")
@@ -52,5 +122,15 @@ public void testWrite(Fory fory) {
     copyCheckWithoutSame(fory, Locale.CHINA);
     copyCheckWithoutSame(fory, Locale.TAIWAN);
     copyCheckWithoutSame(fory, Locale.getDefault());
+    copyCheckWithoutSame(fory, Locale.ROOT);
+    copyCheckWithoutSame(fory, Locale.forLanguageTag("zh-Hans-CN"));
+    copyCheckWithoutSame(fory, Locale.forLanguageTag("sr-Latn-RS"));
+    copyCheckWithoutSame(
+        fory,
+        new Locale.Builder()
+            .setLanguage("th")
+            .setRegion("TH")
+            .setExtension('u', "nu-thai")
+            .build());
   }
 }