diff --git a/src/sagemaker/estimator.py b/src/sagemaker/estimator.py
index 1da3767448..c83a107a2d 100644
--- a/src/sagemaker/estimator.py
+++ b/src/sagemaker/estimator.py
@@ -1713,6 +1713,7 @@ def _stage_user_code_in_s3(self):
             directory=self.source_dir,
             dependencies=self.dependencies,
             kms_key=kms_key,
+            s3_resource=self.sagemaker_session.s3_resource,
         )
 
     def _model_source_dir(self):
diff --git a/src/sagemaker/fw_utils.py b/src/sagemaker/fw_utils.py
index f8479838f0..fa209908b8 100644
--- a/src/sagemaker/fw_utils.py
+++ b/src/sagemaker/fw_utils.py
@@ -307,7 +307,14 @@ def validate_source_dir(script, directory):
 
 
 def tar_and_upload_dir(
-    session, bucket, s3_key_prefix, script, directory=None, dependencies=None, kms_key=None
+    session,
+    bucket,
+    s3_key_prefix,
+    script,
+    directory=None,
+    dependencies=None,
+    kms_key=None,
+    s3_resource=None,
 ):
     """Package source files and upload a compress tar file to S3. The S3
     location will be ``s3://<bucket>/s3_key_prefix/sourcedir.tar.gz``.
@@ -331,6 +338,9 @@ def tar_and_upload_dir(
             copied into /opt/ml/lib
         kms_key (str): Optional. KMS key ID used to upload objects to the bucket
             (default: None).
+        s3_resource (boto3.resource("s3")): Optional. Pre-instantiated Boto3 Resource
+            for S3 connections, can be used to customize the configuration,
+            e.g. set the endpoint URL (default: None).
     Returns:
         sagemaker.fw_utils.UserCode: An object with the S3 bucket and key (S3 prefix) and
             script name.
@@ -354,7 +364,12 @@ def tar_and_upload_dir(
         else:
             extra_args = None
 
-        session.resource("s3").Object(bucket, key).upload_file(tar_file, ExtraArgs=extra_args)
+        if s3_resource is None:
+            s3_resource = session.resource("s3", region_name=session.region_name)
+        else:
+            print("Using provided s3_resource")
+
+        s3_resource.Object(bucket, key).upload_file(tar_file, ExtraArgs=extra_args)
     finally:
         shutil.rmtree(tmp)
 
diff --git a/src/sagemaker/local/image.py b/src/sagemaker/local/image.py
index c2ac5f7575..8fe3550c03 100644
--- a/src/sagemaker/local/image.py
+++ b/src/sagemaker/local/image.py
@@ -46,6 +46,7 @@
 # Environment variables to be set during training
 REGION_ENV_NAME = "AWS_REGION"
 TRAINING_JOB_NAME_ENV_NAME = "TRAINING_JOB_NAME"
+S3_ENDPOINT_URL_ENV_NAME = "S3_ENDPOINT_URL"
 
 logger = logging.getLogger(__name__)
 
@@ -139,6 +140,11 @@ def train(self, input_data_config, output_data_config, hyperparameters, job_name
             REGION_ENV_NAME: self.sagemaker_session.boto_region_name,
             TRAINING_JOB_NAME_ENV_NAME: job_name,
         }
+        if self.sagemaker_session.s3_resource is not None:
+            training_env_vars[
+                S3_ENDPOINT_URL_ENV_NAME
+            ] = self.sagemaker_session.s3_resource.meta.client._endpoint.host
+
         compose_data = self._generate_compose_file(
             "train", additional_volumes=volumes, additional_env_vars=training_env_vars
         )
@@ -206,6 +212,7 @@ def serve(self, model_dir, environment):
             "serve", additional_env_vars=environment, additional_volumes=volumes
         )
         compose_command = self._compose()
+
         self.container = _HostingContainer(compose_command)
         self.container.start()
 
diff --git a/src/sagemaker/local/local_session.py b/src/sagemaker/local/local_session.py
index e407e49e4a..1e80f6e1b4 100644
--- a/src/sagemaker/local/local_session.py
+++ b/src/sagemaker/local/local_session.py
@@ -98,6 +98,7 @@ def create_training_job(
         )
         training_job = _LocalTrainingJob(container)
         hyperparameters = kwargs["HyperParameters"] if "HyperParameters" in kwargs else {}
+        logger.info("Starting training job")
         training_job.start(InputDataConfig, OutputDataConfig, hyperparameters, TrainingJobName)
 
         LocalSagemakerClient._training_jobs[TrainingJobName] = training_job
@@ -377,7 +378,9 @@ def invoke_endpoint(
 class LocalSession(Session):
     """Placeholder docstring"""
 
-    def __init__(self, boto_session=None):
+    def __init__(self, boto_session=None, s3_endpoint_url=None):
+        self.s3_endpoint_url = s3_endpoint_url
+
         super(LocalSession, self).__init__(boto_session)
 
         if platform.system() == "Windows":
@@ -407,6 +410,10 @@ def _initialize(self, boto_session, sagemaker_client, sagemaker_runtime_client):
         self.sagemaker_runtime_client = LocalSagemakerRuntimeClient(self.config)
         self.local_mode = True
 
+        if self.s3_endpoint_url is not None:
+            self.s3_resource = boto_session.resource("s3", endpoint_url=self.s3_endpoint_url)
+            self.s3_client = boto_session.client("s3", endpoint_url=self.s3_endpoint_url)
+
         sagemaker_config_file = os.path.join(os.path.expanduser("~"), ".sagemaker", "config.yaml")
         if os.path.exists(sagemaker_config_file):
             try:
diff --git a/src/sagemaker/multidatamodel.py b/src/sagemaker/multidatamodel.py
index f6eb5682e0..89dbef5ebf 100644
--- a/src/sagemaker/multidatamodel.py
+++ b/src/sagemaker/multidatamodel.py
@@ -92,7 +92,13 @@ def __init__(
         self.model = model
         self.container_mode = MULTI_MODEL_CONTAINER_MODE
         self.sagemaker_session = sagemaker_session or Session()
-        self.s3_client = self.sagemaker_session.boto_session.client("s3")
+
+        if self.sagemaker_session.s3_client is None:
+            self.s3_client = self.sagemaker_session.boto_session.client(
+                "s3", region_name=self.sagemaker_session.boto_session.region_name
+            )
+        else:
+            self.s3_client = self.sagemaker_session.s3_client
 
         # Set the ``Model`` parameters if the model parameter is not specified
         if not self.model:
diff --git a/src/sagemaker/session.py b/src/sagemaker/session.py
index 3ef73f0b15..0dc5bf3161 100644
--- a/src/sagemaker/session.py
+++ b/src/sagemaker/session.py
@@ -107,8 +107,8 @@ def __init__(
         """
         self._default_bucket = None
         self._default_bucket_name_override = default_bucket
-
-        # currently is used for local_code in local mode
+        self.s3_resource = None
+        self.s3_client = None
         self.config = None
 
         self._initialize(
@@ -199,7 +199,10 @@ def upload_data(self, path, bucket=None, key_prefix="data", extra_args=None):
             key_suffix = name
 
         bucket = bucket or self.default_bucket()
-        s3 = self.boto_session.resource("s3")
+        if self.s3_resource is None:
+            s3 = self.boto_session.resource("s3", region_name=self.boto_region_name)
+        else:
+            s3 = self.s3_resource
 
         for local_path, s3_key in files:
             s3.Object(bucket, s3_key).upload_file(local_path, ExtraArgs=extra_args)
@@ -227,7 +230,11 @@ def upload_string_as_file_body(self, body, bucket, key, kms_key=None):
             str: The S3 URI of the uploaded file.
                 The URI format is: ``s3://{bucket name}/{key}``.
         """
-        s3 = self.boto_session.resource("s3")
+        if self.s3_resource is None:
+            s3 = self.boto_session.resource("s3", region_name=self.boto_region_name)
+        else:
+            s3 = self.s3_resource
+
         s3_object = s3.Object(bucket_name=bucket, key=key)
 
         if kms_key is not None:
@@ -254,7 +261,10 @@ def download_data(self, path, bucket, key_prefix="", extra_args=None):
 
         """
         # Initialize the S3 client.
-        s3 = self.boto_session.client("s3")
+        if self.s3_client is None:
+            s3 = self.boto_session.client("s3", region_name=self.boto_region_name)
+        else:
+            s3 = self.s3_client
 
         # Initialize the variables used to loop through the contents of the S3 bucket.
         keys = []
@@ -299,7 +309,10 @@ def read_s3_file(self, bucket, key_prefix):
             str: The body of the s3 file as a string.
 
         """
-        s3 = self.boto_session.client("s3")
+        if self.s3_client is None:
+            s3 = self.boto_session.client("s3", region_name=self.boto_region_name)
+        else:
+            s3 = self.s3_client
 
         # Explicitly passing a None kms_key to boto3 throws a validation error.
         s3_object = s3.get_object(Bucket=bucket, Key=key_prefix)
@@ -317,7 +330,10 @@ def list_s3_files(self, bucket, key_prefix):
             [str]: The list of files at the S3 path.
 
         """
-        s3 = self.boto_session.resource("s3")
+        if self.s3_resource is None:
+            s3 = self.boto_session.resource("s3", region_name=self.boto_region_name)
+        else:
+            s3 = self.s3_resource
 
         s3_bucket = s3.Bucket(name=bucket)
         s3_objects = s3_bucket.objects.filter(Prefix=key_prefix).all()
@@ -330,6 +346,7 @@ def default_bucket(self):
             str: The name of the default bucket, which is of the form:
                 ``sagemaker-{region}-{AWS account ID}``.
         """
+
         if self._default_bucket:
             return self._default_bucket
 
@@ -364,10 +381,14 @@ def _create_s3_bucket_if_it_does_not_exist(self, bucket_name, region):
                 already being created, no exception is raised.
 
         """
-        bucket = self.boto_session.resource("s3", region_name=region).Bucket(name=bucket_name)
+        if self.s3_resource is None:
+            s3 = self.boto_session.resource("s3", region_name=region)
+        else:
+            s3 = self.s3_resource
+
+        bucket = s3.Bucket(name=bucket_name)
         if bucket.creation_date is None:
             try:
-                s3 = self.boto_session.resource("s3", region_name=region)
                 if region == "us-east-1":
                     # 'us-east-1' cannot be specified because it is the default region:
                     # https://github.com/boto/boto3/issues/125
diff --git a/tests/unit/test_airflow.py b/tests/unit/test_airflow.py
index b65fbfa30a..b878069c59 100644
--- a/tests/unit/test_airflow.py
+++ b/tests/unit/test_airflow.py
@@ -36,6 +36,8 @@ def sagemaker_session():
         boto_region_name=REGION,
         config=None,
         local_mode=False,
+        s3_resource=None,
+        s3_client=None,
     )
     session.default_bucket = Mock(name="default_bucket", return_value=BUCKET_NAME)
     session._default_bucket = BUCKET_NAME
diff --git a/tests/unit/test_chainer.py b/tests/unit/test_chainer.py
index 07cf9f5837..4f04e78d55 100644
--- a/tests/unit/test_chainer.py
+++ b/tests/unit/test_chainer.py
@@ -62,6 +62,8 @@ def sagemaker_session():
         boto_region_name=REGION,
         config=None,
         local_mode=False,
+        s3_resource=None,
+        s3_client=None,
     )
 
     describe = {"ModelArtifacts": {"S3ModelArtifacts": "s3://m/m.tar.gz"}}
diff --git a/tests/unit/test_estimator.py b/tests/unit/test_estimator.py
index 3069860b1e..eb8a5e3385 100644
--- a/tests/unit/test_estimator.py
+++ b/tests/unit/test_estimator.py
@@ -174,6 +174,8 @@ def sagemaker_session():
         boto_region_name=REGION,
         config=None,
         local_mode=False,
+        s3_client=None,
+        s3_resource=None,
     )
     sms.default_bucket = Mock(name="default_bucket", return_value=BUCKET_NAME)
     sms.sagemaker_client.describe_training_job = Mock(
diff --git a/tests/unit/test_fm.py b/tests/unit/test_fm.py
index 2b5d0eaba5..5c4ac46900 100644
--- a/tests/unit/test_fm.py
+++ b/tests/unit/test_fm.py
@@ -55,6 +55,8 @@ def sagemaker_session():
         region_name=REGION,
         config=None,
         local_mode=False,
+        s3_client=False,
+        s3_resource=False,
     )
     sms.boto_region_name = REGION
     sms.default_bucket = Mock(name="default_bucket", return_value=BUCKET_NAME)
diff --git a/tests/unit/test_fw_utils.py b/tests/unit/test_fw_utils.py
index 1047533d0f..0f2f49d95c 100644
--- a/tests/unit/test_fw_utils.py
+++ b/tests/unit/test_fw_utils.py
@@ -158,7 +158,9 @@ def cd(path):
 @pytest.fixture()
 def sagemaker_session():
     boto_mock = Mock(name="boto_session", region_name=REGION)
-    session_mock = Mock(name="sagemaker_session", boto_session=boto_mock)
+    session_mock = Mock(
+        name="sagemaker_session", boto_session=boto_mock, s3_client=None, s3_resource=None
+    )
     session_mock.default_bucket = Mock(name="default_bucket", return_value=BUCKET_NAME)
     session_mock.expand_role = Mock(name="expand_role", return_value=ROLE)
     session_mock.sagemaker_client.describe_training_job = Mock(
diff --git a/tests/unit/test_job.py b/tests/unit/test_job.py
index 0a8b86f51f..694f2d7e7a 100644
--- a/tests/unit/test_job.py
+++ b/tests/unit/test_job.py
@@ -73,7 +73,9 @@ def estimator(sagemaker_session):
 @pytest.fixture()
 def sagemaker_session():
     boto_mock = Mock(name="boto_session")
-    mock_session = Mock(name="sagemaker_session", boto_session=boto_mock)
+    mock_session = Mock(
+        name="sagemaker_session", boto_session=boto_mock, s3_client=None, s3_resource=None
+    )
     mock_session.expand_role = Mock(name="expand_role", return_value=ROLE)
 
     return mock_session
diff --git a/tests/unit/test_kmeans.py b/tests/unit/test_kmeans.py
index 7ed837a558..555b78b451 100644
--- a/tests/unit/test_kmeans.py
+++ b/tests/unit/test_kmeans.py
@@ -49,6 +49,8 @@ def sagemaker_session():
         region_name=REGION,
         config=None,
         local_mode=False,
+        s3_client=None,
+        s3_resource=None,
     )
     sms.boto_region_name = REGION
     sms.default_bucket = Mock(name="default_bucket", return_value=BUCKET_NAME)
diff --git a/tests/unit/test_knn.py b/tests/unit/test_knn.py
index 613b3960ea..b839cdefa9 100644
--- a/tests/unit/test_knn.py
+++ b/tests/unit/test_knn.py
@@ -55,6 +55,8 @@ def sagemaker_session():
         region_name=REGION,
         config=None,
         local_mode=False,
+        s3_client=None,
+        s3_resource=None,
     )
     sms.boto_region_name = REGION
     sms.default_bucket = Mock(name="default_bucket", return_value=BUCKET_NAME)
diff --git a/tests/unit/test_lda.py b/tests/unit/test_lda.py
index 91a543e938..4bb4d5a594 100644
--- a/tests/unit/test_lda.py
+++ b/tests/unit/test_lda.py
@@ -39,7 +39,14 @@
 @pytest.fixture()
 def sagemaker_session():
     boto_mock = Mock(name="boto_session", region_name=REGION)
-    sms = Mock(name="sagemaker_session", boto_session=boto_mock, config=None, local_mode=False)
+    sms = Mock(
+        name="sagemaker_session",
+        boto_session=boto_mock,
+        config=None,
+        local_mode=False,
+        s3_client=None,
+        s3_resource=None,
+    )
     sms.boto_region_name = REGION
     sms.default_bucket = Mock(name="default_bucket", return_value=BUCKET_NAME)
     sms.sagemaker_client.describe_training_job = Mock(
diff --git a/tests/unit/test_linear_learner.py b/tests/unit/test_linear_learner.py
index ed466b8954..3b16e85c02 100644
--- a/tests/unit/test_linear_learner.py
+++ b/tests/unit/test_linear_learner.py
@@ -50,6 +50,8 @@ def sagemaker_session():
         region_name=REGION,
         config=None,
         local_mode=False,
+        s3_client=None,
+        s3_resource=None,
     )
     sms.boto_region_name = REGION
     sms.default_bucket = Mock(name="default_bucket", return_value=BUCKET_NAME)
diff --git a/tests/unit/test_local_session.py b/tests/unit/test_local_session.py
index ad7bc0fb85..a263d6b640 100644
--- a/tests/unit/test_local_session.py
+++ b/tests/unit/test_local_session.py
@@ -14,9 +14,10 @@
 
 import pytest
 import urllib3
-
+import os
 from botocore.exceptions import ClientError
 from mock import Mock, patch
+from tests.unit import DATA_DIR
 
 import sagemaker
 
@@ -33,6 +34,10 @@
 MODEL_NAME = "test-model"
 PRIMARY_CONTAINER = {"ModelDataUrl": "/some/model/path", "Environment": {"env1": 1, "env2": "b"}}
 
+ENDPOINT_URL = "http://127.0.0.1:9000"
+BUCKET_NAME = "mybucket"
+LS_FILES = {"Contents": [{"Key": "/data/test.csv"}]}
+
 
 @patch("sagemaker.local.image._SageMakerContainer.train", return_value="/some/path/to/model")
 @patch("sagemaker.local.local_session.LocalSession")
@@ -475,3 +480,53 @@ def test_local_session_is_set_to_local_mode():
     boto_session = Mock(region_name="us-west-2")
     local_session = sagemaker.local.local_session.LocalSession(boto_session=boto_session)
     assert local_session.local_mode
+
+
+@pytest.fixture()
+def sagemaker_session_custom_endpoint():
+
+    boto_session = Mock("boto_session")
+    resource_mock = Mock("resource")
+    client_mock = Mock("client")
+    boto_attrs = {"region_name": "us-east-1"}
+    boto_session.configure_mock(**boto_attrs)
+    boto_session.resource = Mock(name="resource", return_value=resource_mock)
+    boto_session.client = Mock(name="client", return_value=client_mock)
+
+    local_session = sagemaker.local.local_session.LocalSession(
+        boto_session=boto_session, s3_endpoint_url=ENDPOINT_URL
+    )
+
+    local_session.default_bucket = Mock(name="default_bucket", return_value=BUCKET_NAME)
+    return local_session
+
+
+def test_local_session_with_custom_s3_endpoint_url(sagemaker_session_custom_endpoint):
+
+    boto_session = sagemaker_session_custom_endpoint.boto_session
+
+    boto_session.client.assert_called_with("s3", endpoint_url=ENDPOINT_URL)
+    boto_session.resource.assert_called_with("s3", endpoint_url=ENDPOINT_URL)
+
+    assert sagemaker_session_custom_endpoint.s3_client is not None
+    assert sagemaker_session_custom_endpoint.s3_resource is not None
+
+
+def test_local_session_download_with_custom_s3_endpoint_url(sagemaker_session_custom_endpoint):
+
+    DOWNLOAD_DATA_TESTS_FILES_DIR = os.path.join(DATA_DIR, "download_data_tests")
+    sagemaker_session_custom_endpoint.s3_client.list_objects_v2 = Mock(
+        name="list_objects_v2", return_value=LS_FILES
+    )
+    sagemaker_session_custom_endpoint.s3_client.download_file = Mock(name="download_file")
+
+    sagemaker_session_custom_endpoint.download_data(
+        DOWNLOAD_DATA_TESTS_FILES_DIR, BUCKET_NAME, key_prefix="/data/test.csv"
+    )
+
+    sagemaker_session_custom_endpoint.s3_client.download_file.assert_called_with(
+        Bucket=BUCKET_NAME,
+        Key="/data/test.csv",
+        Filename="{}/{}".format(DOWNLOAD_DATA_TESTS_FILES_DIR, "test.csv"),
+        ExtraArgs=None,
+    )
diff --git a/tests/unit/test_model.py b/tests/unit/test_model.py
index 82c42ae049..d25d267551 100644
--- a/tests/unit/test_model.py
+++ b/tests/unit/test_model.py
@@ -130,6 +130,8 @@ def sagemaker_session():
         boto_region_name=REGION,
         config=None,
         local_mode=False,
+        s3_client=None,
+        s3_resource=None,
     )
     sms.default_bucket = Mock(name="default_bucket", return_value=BUCKET_NAME)
     return sms
diff --git a/tests/unit/test_multidatamodel.py b/tests/unit/test_multidatamodel.py
index edcd7df621..84aed3fc58 100644
--- a/tests/unit/test_multidatamodel.py
+++ b/tests/unit/test_multidatamodel.py
@@ -64,6 +64,8 @@ def sagemaker_session():
         boto_region_name=REGION,
         config=None,
         local_mode=False,
+        s3_resource=None,
+        s3_client=None,
     )
     session.sagemaker_client.describe_endpoint = Mock(return_value=ENDPOINT_DESC)
     session.sagemaker_client.describe_endpoint_config = Mock(return_value=ENDPOINT_CONFIG_DESC)
diff --git a/tests/unit/test_mxnet.py b/tests/unit/test_mxnet.py
index e1bd92e233..3bd3111516 100644
--- a/tests/unit/test_mxnet.py
+++ b/tests/unit/test_mxnet.py
@@ -71,6 +71,8 @@ def sagemaker_session():
         boto_region_name=REGION,
         config=None,
         local_mode=False,
+        s3_resource=None,
+        s3_client=None,
     )
 
     describe = {"ModelArtifacts": {"S3ModelArtifacts": "s3://m/m.tar.gz"}}
diff --git a/tests/unit/test_ntm.py b/tests/unit/test_ntm.py
index 1f843e04d7..6fddd4b475 100644
--- a/tests/unit/test_ntm.py
+++ b/tests/unit/test_ntm.py
@@ -49,6 +49,8 @@ def sagemaker_session():
         region_name=REGION,
         config=None,
         local_mode=False,
+        s3_client=None,
+        s3_resource=None,
     )
     sms.boto_region_name = REGION
     sms.default_bucket = Mock(name="default_bucket", return_value=BUCKET_NAME)
diff --git a/tests/unit/test_object2vec.py b/tests/unit/test_object2vec.py
index cde721d6f9..9c4175fdec 100644
--- a/tests/unit/test_object2vec.py
+++ b/tests/unit/test_object2vec.py
@@ -57,6 +57,8 @@ def sagemaker_session():
         region_name=REGION,
         config=None,
         local_mode=False,
+        s3_client=None,
+        s3_resource=None,
     )
     sms.boto_region_name = REGION
     sms.default_bucket = Mock(name="default_bucket", return_value=BUCKET_NAME)
diff --git a/tests/unit/test_pca.py b/tests/unit/test_pca.py
index 5e6bed83b7..ffa6bafe19 100644
--- a/tests/unit/test_pca.py
+++ b/tests/unit/test_pca.py
@@ -49,6 +49,8 @@ def sagemaker_session():
         region_name=REGION,
         config=None,
         local_mode=False,
+        s3_client=None,
+        s3_resource=None,
     )
     sms.boto_region_name = REGION
     sms.default_bucket = Mock(name="default_bucket", return_value=BUCKET_NAME)
diff --git a/tests/unit/test_pipeline_model.py b/tests/unit/test_pipeline_model.py
index 31ac46704a..114920fa5b 100644
--- a/tests/unit/test_pipeline_model.py
+++ b/tests/unit/test_pipeline_model.py
@@ -66,6 +66,8 @@ def sagemaker_session():
         boto_region_name=REGION,
         config=None,
         local_mode=False,
+        s3_client=None,
+        s3_resource=None,
     )
     sms.default_bucket = Mock(name="default_bucket", return_value=BUCKET_NAME)
     return sms
diff --git a/tests/unit/test_pytorch.py b/tests/unit/test_pytorch.py
index 9d984ab5e0..04cb8f0cbf 100644
--- a/tests/unit/test_pytorch.py
+++ b/tests/unit/test_pytorch.py
@@ -65,6 +65,8 @@ def fixture_sagemaker_session():
         boto_region_name=REGION,
         config=None,
         local_mode=False,
+        s3_resource=None,
+        s3_client=None,
     )
 
     describe = {"ModelArtifacts": {"S3ModelArtifacts": "s3://m/m.tar.gz"}}
diff --git a/tests/unit/test_rl.py b/tests/unit/test_rl.py
index a1a82cf3d5..80c5a02336 100644
--- a/tests/unit/test_rl.py
+++ b/tests/unit/test_rl.py
@@ -62,6 +62,8 @@ def fixture_sagemaker_session():
         boto_region_name=REGION,
         config=None,
         local_mode=False,
+        s3_resource=None,
+        s3_client=None,
     )
 
     describe = {"ModelArtifacts": {"S3ModelArtifacts": "s3://m/m.tar.gz"}}
diff --git a/tests/unit/test_sklearn.py b/tests/unit/test_sklearn.py
index de41d16fb9..7b23f69c9e 100644
--- a/tests/unit/test_sklearn.py
+++ b/tests/unit/test_sklearn.py
@@ -64,6 +64,8 @@ def sagemaker_session():
         boto_region_name=REGION,
         config=None,
         local_mode=False,
+        s3_resource=None,
+        s3_client=None,
     )
 
     describe = {"ModelArtifacts": {"S3ModelArtifacts": "s3://m/m.tar.gz"}}
diff --git a/tests/unit/test_tf_estimator.py b/tests/unit/test_tf_estimator.py
index d7ec041ca4..f8ec996d62 100644
--- a/tests/unit/test_tf_estimator.py
+++ b/tests/unit/test_tf_estimator.py
@@ -74,6 +74,8 @@ def sagemaker_session():
         boto_region_name=REGION,
         config=None,
         local_mode=False,
+        s3_resource=None,
+        s3_client=None,
     )
     session.default_bucket = Mock(name="default_bucket", return_value=BUCKET_NAME)
     session.expand_role = Mock(name="expand_role", return_value=ROLE)
diff --git a/tests/unit/test_tfs.py b/tests/unit/test_tfs.py
index 0b915a710c..8de1a5424d 100644
--- a/tests/unit/test_tfs.py
+++ b/tests/unit/test_tfs.py
@@ -57,6 +57,8 @@ def sagemaker_session():
         boto_region_name=REGION,
         config=None,
         local_mode=False,
+        s3_resource=None,
+        s3_client=None,
     )
     session.default_bucket = Mock(name="default_bucket", return_value="my_bucket")
     session.expand_role = Mock(name="expand_role", return_value=ROLE)
diff --git a/tests/unit/test_tuner.py b/tests/unit/test_tuner.py
index 29a503ff1e..490ae96145 100644
--- a/tests/unit/test_tuner.py
+++ b/tests/unit/test_tuner.py
@@ -40,7 +40,7 @@
 @pytest.fixture()
 def sagemaker_session():
     boto_mock = Mock(name="boto_session", region_name=REGION)
-    sms = Mock(name="sagemaker_session", boto_session=boto_mock)
+    sms = Mock(name="sagemaker_session", boto_session=boto_mock, s3_client=None, s3_resource=None)
     sms.boto_region_name = REGION
     sms.default_bucket = Mock(name="default_bucket", return_value=BUCKET_NAME)
     sms.config = None
diff --git a/tests/unit/test_upload_data.py b/tests/unit/test_upload_data.py
index 7c0ec51608..e2fab2e6c7 100644
--- a/tests/unit/test_upload_data.py
+++ b/tests/unit/test_upload_data.py
@@ -25,6 +25,7 @@
 UPLOAD_DATA_TESTS_SINGLE_FILE = os.path.join(UPLOAD_DATA_TESTS_FILES_DIR, SINGLE_FILE_NAME)
 BUCKET_NAME = "mybucket"
 AES_ENCRYPTION_ENABLED = {"ServerSideEncryption": "AES256"}
+ENDPOINT_URL = "http://127.0.0.1:9000"
 
 
 @pytest.fixture()
@@ -35,6 +36,25 @@ def sagemaker_session():
     return ims
 
 
+@pytest.fixture()
+def sagemaker_session_custom_endpoint():
+
+    boto_session = Mock("boto_session")
+    resource_mock = Mock("resource")
+    client_mock = Mock("client")
+    boto_attrs = {"region_name": "us-east-1"}
+    boto_session.configure_mock(**boto_attrs)
+    boto_session.resource = Mock(name="resource", return_value=resource_mock)
+    boto_session.client = Mock(name="client", return_value=client_mock)
+
+    local_session = sagemaker.local.local_session.LocalSession(
+        boto_session=boto_session, s3_endpoint_url=ENDPOINT_URL
+    )
+
+    local_session.default_bucket = Mock(name="default_bucket", return_value=BUCKET_NAME)
+    return local_session
+
+
 def test_upload_data_absolute_dir(sagemaker_session):
     result_s3_uri = sagemaker_session.upload_data(UPLOAD_DATA_TESTS_FILES_DIR)
 
@@ -50,6 +70,24 @@ def test_upload_data_absolute_dir(sagemaker_session):
         assert kwargs["ExtraArgs"] is None
 
 
+def test_upload_data_absolute_dir_custom_endpoint(sagemaker_session_custom_endpoint):
+
+    sagemaker_session_custom_endpoint.s3_resource.Object = Mock()
+
+    result_s3_uri = sagemaker_session_custom_endpoint.upload_data(UPLOAD_DATA_TESTS_FILES_DIR)
+
+    uploaded_files_with_args = [
+        (args[0], kwargs)
+        for name, args, kwargs in sagemaker_session_custom_endpoint.s3_resource.mock_calls
+        if name == "Object().upload_file"
+    ]
+    assert result_s3_uri == "s3://{}/data".format(BUCKET_NAME)
+    assert len(uploaded_files_with_args) == 4
+    for file, kwargs in uploaded_files_with_args:
+        assert os.path.exists(file)
+        assert kwargs["ExtraArgs"] is None
+
+
 def test_upload_data_absolute_file(sagemaker_session):
     result_s3_uri = sagemaker_session.upload_data(UPLOAD_DATA_TESTS_SINGLE_FILE)
 
diff --git a/tests/unit/test_xgboost.py b/tests/unit/test_xgboost.py
index 6ef43bea58..35b8b6acd4 100644
--- a/tests/unit/test_xgboost.py
+++ b/tests/unit/test_xgboost.py
@@ -65,6 +65,8 @@ def sagemaker_session():
         boto_region_name=REGION,
         config=None,
         local_mode=False,
+        s3_resource=None,
+        s3_client=None,
     )
 
     describe = {"ModelArtifacts": {"S3ModelArtifacts": "s3://m/m.tar.gz"}}