diff --git a/boto3/dynamodb/types.py b/boto3/dynamodb/types.py
index f358b12f55..a3f989e8f6 100644
--- a/boto3/dynamodb/types.py
+++ b/boto3/dynamodb/types.py
@@ -33,7 +33,8 @@
 MAP = 'M'
 LIST = 'L'
 
-
+# Retained for backwards compatibility; serializer/deserializer no longer use
+# this context for number handling.
 DYNAMODB_CONTEXT = Context(
     Emin=-128,
     Emax=126,
@@ -211,10 +212,10 @@ def _serialize_bool(self, value):
         return value
 
     def _serialize_n(self, value):
-        number = str(DYNAMODB_CONTEXT.create_decimal(value))
-        if number in ['Infinity', 'NaN']:
+        decimal_value = Decimal(value)
+        if decimal_value.is_nan() or decimal_value.is_infinite():
             raise TypeError('Infinity and NaN not supported')
-        return number
+        return str(decimal_value)
 
     def _serialize_s(self, value):
         return value
@@ -286,7 +287,7 @@ def _deserialize_bool(self, value):
         return value
 
     def _deserialize_n(self, value):
-        return DYNAMODB_CONTEXT.create_decimal(value)
+        return Decimal(value)
 
     def _deserialize_s(self, value):
         return value
diff --git a/tests/unit/dynamodb/test_types.py b/tests/unit/dynamodb/test_types.py
index 0a6c2a07f3..903da07ee7 100644
--- a/tests/unit/dynamodb/test_types.py
+++ b/tests/unit/dynamodb/test_types.py
@@ -85,6 +85,10 @@ def test_serialize_NaN_error(self):
         with pytest.raises(TypeError, match=r'Infinity and NaN not supported'):
             self.serializer.serialize(Decimal('NaN'))
 
+    def test_serialize_infinity_error(self):
+        with pytest.raises(TypeError, match=r'Infinity and NaN not supported'):
+            self.serializer.serialize(Decimal('-Infinity'))
+
     def test_serialize_string(self):
         assert self.serializer.serialize('foo') == {'S': 'foo'}
 
@@ -143,6 +147,21 @@ def test_serialize_map(self):
             'M': {'foo': {'S': 'bar'}, 'baz': {'M': {'biz': {'N': '1'}}}}
         }
 
+    def test_serialize_large_number_with_trailing_zeros(self):
+        assert self.serializer.serialize(
+            1234567895171680000000000000000000000000
+        ) == {'N': '1234567895171680000000000000000000000000'}
+
+    def test_serialize_large_decimal_with_trailing_zeros(self):
+        assert self.serializer.serialize(
+            Decimal('1234567895171680000000000000000000000000')
+        ) == {'N': '1234567895171680000000000000000000000000'}
+
+    def test_serialize_large_decimal_defers_validation_to_dynamodb(self):
+        assert self.serializer.serialize(Decimal('9' * 39)) == {
+            'N': '999999999999999999999999999999999999999'
+        }
+
 
 class TestDeserializer(unittest.TestCase):
     def setUp(self):
@@ -206,3 +225,16 @@ def test_deserialize_map(self):
                 }
             }
         ) == {'foo': 'mystring', 'bar': {'baz': Decimal('1')}}
+
+    def test_deserialize_large_number_with_trailing_zeros(self):
+        # Numbers with trailing zeros that exceed 38 total digits but have
+        # <=38 significant digits are valid in DynamoDB and must deserialize.
+        large_num = '1234567895171680000000000000000000000000'
+        result = self.deserializer.deserialize({'N': large_num})
+        assert result == Decimal(large_num)
+        assert str(result) == large_num
+
+    def test_deserialize_and_serialize_large_number_with_trailing_zeros(self):
+        large_num = '1234567895171680000000000000000000000000'
+        result = self.deserializer.deserialize({'N': large_num})
+        assert TypeSerializer().serialize(result) == {'N': large_num}