diff --git a/isthmus/src/main/java/io/substrait/isthmus/SubstraitTypeSystem.java b/isthmus/src/main/java/io/substrait/isthmus/SubstraitTypeSystem.java
index 0949584b0..2666af438 100644
--- a/isthmus/src/main/java/io/substrait/isthmus/SubstraitTypeSystem.java
+++ b/isthmus/src/main/java/io/substrait/isthmus/SubstraitTypeSystem.java
@@ -91,7 +91,6 @@ public int getMaxPrecision(final SqlTypeName typeName) {
       case INTERVAL_YEAR:
       case INTERVAL_YEAR_MONTH:
       case TIME:
-      case TIME_WITH_LOCAL_TIME_ZONE:
       case TIMESTAMP:
       case TIMESTAMP_WITH_LOCAL_TIME_ZONE:
         return 6;
diff --git a/isthmus/src/test/java/io/substrait/isthmus/SubstraitTypeSystemTest.java b/isthmus/src/test/java/io/substrait/isthmus/SubstraitTypeSystemTest.java
index 01e7bd0c7..159816c6f 100644
--- a/isthmus/src/test/java/io/substrait/isthmus/SubstraitTypeSystemTest.java
+++ b/isthmus/src/test/java/io/substrait/isthmus/SubstraitTypeSystemTest.java
@@ -2,6 +2,7 @@
 
 import static io.substrait.isthmus.SubstraitTypeSystem.TYPE_FACTORY;
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.apache.calcite.rel.type.RelDataType;
 import org.apache.calcite.rel.type.RelDataTypeSystem;
@@ -42,6 +43,20 @@ void timeMaxPrecision() {
     assertEquals(6, typeSystem.getMaxPrecision(SqlTypeName.TIME));
   }
 
+  @Test
+  void timeWithLocalTimeZoneHasNoSubstraitMaxPrecision() {
+    // Substrait has precision_timestamp_tz but no time-with-timezone counterpart, so this type
+    // converts in neither direction and there is no Substrait maximum to report for it.
+    assertThrows(
+        UnsupportedOperationException.class,
+        () ->
+            TypeConverter.DEFAULT.toSubstrait(
+                TYPE_FACTORY.createSqlType(SqlTypeName.TIME_WITH_LOCAL_TIME_ZONE, 3)));
+    assertEquals(
+        RelDataTypeSystem.DEFAULT.getMaxPrecision(SqlTypeName.TIME_WITH_LOCAL_TIME_ZONE),
+        typeSystem.getMaxPrecision(SqlTypeName.TIME_WITH_LOCAL_TIME_ZONE));
+  }
+
   @Test
   void canCreateDecimalWithMaxPrecision() {
     RelDataType decimalType = TYPE_FACTORY.createSqlType(SqlTypeName.DECIMAL, 38, 10);