diff --git a/openapi_schema_validator/_format.py b/openapi_schema_validator/_format.py
index 415f556..0fb9e97 100644
--- a/openapi_schema_validator/_format.py
+++ b/openapi_schema_validator/_format.py
@@ -7,6 +7,7 @@
 from jsonschema.exceptions import FormatError
 from six import binary_type, text_type, integer_types
 
+DATETIME_HAS_RFC3339_VALIDATOR = False
 DATETIME_HAS_STRICT_RFC3339 = False
 DATETIME_HAS_ISODATE = False
 DATETIME_RAISES = ()
@@ -19,6 +20,14 @@
     DATETIME_HAS_ISODATE = True
     DATETIME_RAISES += (ValueError, isodate.ISO8601Error)
 
+try:
+    from rfc3339_validator import validate_rfc3339
+except ImportError:
+    pass
+else:
+    DATETIME_HAS_RFC3339_VALIDATOR = True
+    DATETIME_RAISES += (ValueError, TypeError)
+
 try:
     import strict_rfc3339
 except ImportError:
@@ -64,6 +73,9 @@ def is_datetime(instance):
     if not isinstance(instance, (binary_type, text_type)):
         return False
 
+    if DATETIME_HAS_RFC3339_VALIDATOR:
+        return validate_rfc3339(instance)
+
     if DATETIME_HAS_STRICT_RFC3339:
         return strict_rfc3339.validate_rfc3339(instance)
 
diff --git a/requirements.txt b/requirements.txt
index b66d10e..6643606 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,5 @@
 isodate
 jsonschema
 six
-strict_rfc3339
+strict-rfc3339
+rfc3339-validator
diff --git a/setup.cfg b/setup.cfg
index b6efdbe..0755699 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -29,13 +29,20 @@ install_requires =
     isodate
     jsonschema>=3.0.0
     six
-    strict_rfc3339
 tests_require =
     mock; python_version<"3.0"
     pytest
     pytest-flake8
     pytest-cov
 
+[options.extras_require]
+rfc3339-validator = 
+    rfc3339-validator
+strict-rfc3339 =
+    strict-rfc3339
+isodate =
+    isodate
+
 [options.packages.find]
 exclude =
     tests
diff --git a/tests/integration/test_validators.py b/tests/integration/test_validators.py
index 8c50aa8..6ab8f8c 100644
--- a/tests/integration/test_validators.py
+++ b/tests/integration/test_validators.py
@@ -35,6 +35,60 @@ def test_nullable(self, schema_type):
         u('1989-01-02T00:00:00Z'),
         u('2018-01-02T23:59:59Z'),
     ])
+    @mock.patch(
+        'openapi_schema_validator._format.'
+        'DATETIME_HAS_RFC3339_VALIDATOR', False
+    )
+    @mock.patch(
+        'openapi_schema_validator._format.'
+        'DATETIME_HAS_STRICT_RFC3339', False
+    )
+    @mock.patch(
+        'openapi_schema_validator._format.'
+        'DATETIME_HAS_ISODATE', False
+    )
+    def test_string_format_no_datetime_validator(self, value):
+        schema = {"type": 'string', "format": 'date-time'}
+        validator = OAS30Validator(
+            schema, format_checker=oas30_format_checker)
+
+        result = validator.validate(value)
+
+        assert result is None
+
+    @pytest.mark.parametrize('value', [
+        u('1989-01-02T00:00:00Z'),
+        u('2018-01-02T23:59:59Z'),
+    ])
+    @mock.patch(
+        'openapi_schema_validator._format.'
+        'DATETIME_HAS_RFC3339_VALIDATOR', True
+    )
+    @mock.patch(
+        'openapi_schema_validator._format.'
+        'DATETIME_HAS_STRICT_RFC3339', False
+    )
+    @mock.patch(
+        'openapi_schema_validator._format.'
+        'DATETIME_HAS_ISODATE', False
+    )
+    def test_string_format_datetime_rfc3339_validator(self, value):
+        schema = {"type": 'string', "format": 'date-time'}
+        validator = OAS30Validator(
+            schema, format_checker=oas30_format_checker)
+
+        result = validator.validate(value)
+
+        assert result is None
+
+    @pytest.mark.parametrize('value', [
+        u('1989-01-02T00:00:00Z'),
+        u('2018-01-02T23:59:59Z'),
+    ])
+    @mock.patch(
+        'openapi_schema_validator._format.'
+        'DATETIME_HAS_RFC3339_VALIDATOR', False
+    )
     @mock.patch(
         'openapi_schema_validator._format.'
         'DATETIME_HAS_STRICT_RFC3339', True
@@ -56,6 +110,10 @@ def test_string_format_datetime_strict_rfc3339(self, value):
         u('1989-01-02T00:00:00Z'),
         u('2018-01-02T23:59:59Z'),
     ])
+    @mock.patch(
+        'openapi_schema_validator._format.'
+        'DATETIME_HAS_RFC3339_VALIDATOR', False
+    )
     @mock.patch(
         'openapi_schema_validator._format.'
         'DATETIME_HAS_STRICT_RFC3339', False