diff --git a/native/core/src/parquet/schema_adapter.rs b/native/core/src/parquet/schema_adapter.rs
index f19ec39fca..491f0a8e85 100644
--- a/native/core/src/parquet/schema_adapter.rs
+++ b/native/core/src/parquet/schema_adapter.rs
@@ -302,10 +302,11 @@ impl SparkPhysicalExprAdapter {
             let physical_type = cast.input_field().data_type();
             let target_type = cast.target_field().data_type();
 
-            // For complex nested types (Struct, List, Map) and Timestamp timezone
-            // mismatches, use CometCastColumnExpr with spark_parquet_convert which
-            // handles field-name-based selection, reordering, nested type casting,
-            // and metadata-only timestamp timezone relabeling correctly.
+            // For complex nested types (Struct, List, Map), Timestamp timezone
+            // mismatches, and Timestamp→Int64 (nanosAsLong), use CometCastColumnExpr
+            // with spark_parquet_convert which handles field-name-based selection,
+            // reordering, nested type casting, metadata-only timestamp timezone
+            // relabeling, and raw value reinterpretation correctly.
             //
             // Timestamp mismatches (e.g., Timestamp(us, None) -> Timestamp(us, Some("UTC")))
             // occur when INT96 Parquet timestamps are coerced to Timestamp(us, None) by
@@ -313,12 +314,18 @@ impl SparkPhysicalExprAdapter {
             // Using Spark's Cast here would incorrectly treat the None-timezone values as
             // local time (TimestampNTZ) and apply a timezone conversion, but the values are
             // already in UTC. spark_parquet_convert handles this as a metadata-only change.
+            //
+            // Timestamp→Int64 occurs when Spark's `nanosAsLong` config converts
+            // TIMESTAMP(NANOS) to LongType. Spark's Cast would divide by MICROS_PER_SECOND
+            // (assuming microseconds), but the values are nanoseconds. Arrow cast correctly
+            // reinterprets the raw i64 value without conversion.
             if matches!(
                 (physical_type, target_type),
                 (DataType::Struct(_), DataType::Struct(_))
                     | (DataType::List(_), DataType::List(_))
                     | (DataType::Map(_, _), DataType::Map(_, _))
                     | (DataType::Timestamp(_, _), DataType::Timestamp(_, _))
+                    | (DataType::Timestamp(_, _), DataType::Int64)
             ) {
                 let comet_cast: Arc<dyn PhysicalExpr> = Arc::new(
                     CometCastColumnExpr::new(