diff --git a/client-v2/src/main/java/com/clickhouse/client/api/DataTypeUtils.java b/client-v2/src/main/java/com/clickhouse/client/api/DataTypeUtils.java
index cc451aef6..ea67265a2 100644
--- a/client-v2/src/main/java/com/clickhouse/client/api/DataTypeUtils.java
+++ b/client-v2/src/main/java/com/clickhouse/client/api/DataTypeUtils.java
@@ -219,7 +219,7 @@ public static String durationToTimeString(Duration duration, int precision) {
         if (precision > 0 && precision <= 9) {
             sb.append('.');
             // Format nanos with leading zeros, then truncate to precision
-            String nanosStr = String.format("%09d", nanos);
+            String nanosStr = String.format(java.util.Locale.ROOT, "%09d", nanos);
             sb.append(nanosStr, 0, precision);
         }
 
diff --git a/client-v2/src/test/java/com/clickhouse/client/api/DataTypeUtilsTests.java b/client-v2/src/test/java/com/clickhouse/client/api/DataTypeUtilsTests.java
index 54f9a7000..e22cb4e8c 100644
--- a/client-v2/src/test/java/com/clickhouse/client/api/DataTypeUtilsTests.java
+++ b/client-v2/src/test/java/com/clickhouse/client/api/DataTypeUtilsTests.java
@@ -501,4 +501,16 @@ void testRoundTripConversionsWithDifferentTimezones() {
         assertEquals(dateTimeInNy.toLocalDate(), LocalDate.of(2024, 7, 4).minusDays(1),
                 "Same instant should be previous day in New York");
     }
+
+    @Test(groups = {"unit"})
+    public void testDurationToTimeStringIgnoresDefaultLocale() {
+        java.util.Locale original = java.util.Locale.getDefault();
+        try {
+            java.util.Locale.setDefault(java.util.Locale.forLanguageTag("fa-IR"));
+            assertEquals(DataTypeUtils.durationToTimeString(Duration.ofSeconds(3661, 123456789), 9), "1:01:01.123456789");
+            assertEquals(DataTypeUtils.durationToTimeString(Duration.ofSeconds(1, 5000000), 3), "0:00:01.005");
+        } finally {
+            java.util.Locale.setDefault(original);
+        }
+    }
 }
diff --git a/history/latest/3308.md b/history/latest/3308.md
new file mode 100644
index 000000000..5b0e52f8e
--- /dev/null
+++ b/history/latest/3308.md
@@ -0,0 +1 @@
+- **[client-v2, jdbc-v2]** Fixed `Duration`/`Time64` parameter rendered with non-ASCII digits under locales like fa-IR/ar-SA (`String.format` used the default locale); now `Locale.ROOT`. (https://github.com/ClickHouse/clickhouse-java/issues/3308)