diff --git a/python/ray/tune/config_parser.py b/python/ray/tune/config_parser.py
index 67fd5a665..06d6d7a97 100644
--- a/python/ray/tune/config_parser.py
+++ b/python/ray/tune/config_parser.py
@@ -202,6 +202,7 @@ def create_trial_from_spec(spec, output_path, parser, **trial_kwargs):
         # json.load leads to str -> unicode in py2.7
         stopping_criterion=spec.get("stop", {}),
         remote_checkpoint_dir=spec.get("remote_checkpoint_dir"),
+        sync_to_cloud=spec.get("sync_to_cloud"),
         checkpoint_freq=args.checkpoint_freq,
         checkpoint_at_end=args.checkpoint_at_end,
         sync_on_checkpoint=args.sync_on_checkpoint,
diff --git a/python/ray/tune/durable_trainable.py b/python/ray/tune/durable_trainable.py
index aba1d9839..0ca3c692d 100644
--- a/python/ray/tune/durable_trainable.py
+++ b/python/ray/tune/durable_trainable.py
@@ -1,4 +1,4 @@
-from typing import Callable, Type, Union
+from typing import Callable, Optional, Type, Union
 
 import inspect
 import logging
@@ -6,6 +6,7 @@ import os
 
 from ray.tune.function_runner import wrap_function
 from ray.tune.registry import get_trainable_cls
+from ray.tune.sync_client import get_sync_client
 from ray.tune.trainable import Trainable, TrainableUtil
 from ray.tune.syncer import get_cloud_sync_client
 
@@ -31,15 +32,23 @@ class DurableTrainable(Trainable):
 
     >>> tune.run(MyDurableTrainable, sync_to_driver=False)
     """
+    _sync_function_tpl = None
 
-    def __init__(self, remote_checkpoint_dir, *args, **kwargs):
+    def __init__(self,
+                 remote_checkpoint_dir: str,
+                 sync_function_tpl: Optional[str] = None,
+                 *args,
+                 **kwargs):
         """Initializes a DurableTrainable.
 
         Args:
             remote_checkpoint_dir (str): Upload directory (S3 or GS path).
+            sync_function_tpl (str): Sync function template to use. Defaults
+              to `cls._sync_function` (which defaults to `None`).
         """
         super(DurableTrainable, self).__init__(*args, **kwargs)
         self.remote_checkpoint_dir = remote_checkpoint_dir
+        self.sync_function_tpl = sync_function_tpl or self._sync_function_tpl
         self.storage_client = self._create_storage_client()
 
     def save(self, checkpoint_dir=None):
@@ -96,7 +105,9 @@ class DurableTrainable(Trainable):
 
     def _create_storage_client(self):
         """Returns a storage client."""
-        return get_cloud_sync_client(self.remote_checkpoint_dir)
+        return get_sync_client(
+            self.sync_function_tpl) or get_cloud_sync_client(
+                self.remote_checkpoint_dir)
 
     def _storage_path(self, local_path):
         rel_local_path = os.path.relpath(local_path, self.logdir)
diff --git a/python/ray/tune/experiment.py b/python/ray/tune/experiment.py
index 5c18f48e4..51db759f4 100644
--- a/python/ray/tune/experiment.py
+++ b/python/ray/tune/experiment.py
@@ -115,6 +115,7 @@ class Experiment:
                  loggers=None,
                  log_to_file=False,
                  sync_to_driver=None,
+                 sync_to_cloud=None,
                  checkpoint_freq=0,
                  checkpoint_at_end=False,
                  sync_on_checkpoint=True,
@@ -217,6 +218,7 @@ class Experiment:
             "loggers": loggers,
             "log_to_file": (stdout_file, stderr_file),
             "sync_to_driver": sync_to_driver,
+            "sync_to_cloud": sync_to_cloud,
             "checkpoint_freq": checkpoint_freq,
             "checkpoint_at_end": checkpoint_at_end,
             "sync_on_checkpoint": sync_on_checkpoint,
diff --git a/python/ray/tune/ray_trial_executor.py b/python/ray/tune/ray_trial_executor.py
index 5221a133f..ee7e7e461 100644
--- a/python/ray/tune/ray_trial_executor.py
+++ b/python/ray/tune/ray_trial_executor.py
@@ -361,6 +361,7 @@ class RayTrialExecutor(TrialExecutor):
         }
         if issubclass(trial.get_trainable_cls(), DurableTrainable):
             kwargs["remote_checkpoint_dir"] = trial.remote_checkpoint_dir
+            kwargs["sync_function_tpl"] = trial.sync_to_cloud
 
         with self._change_working_directory(trial):
             return full_actor_class.remote(**kwargs)
diff --git a/python/ray/tune/tests/test_api.py b/python/ray/tune/tests/test_api.py
index 0638ffa04..cf7454a4f 100644
--- a/python/ray/tune/tests/test_api.py
+++ b/python/ray/tune/tests/test_api.py
@@ -21,6 +21,7 @@ from ray.tune.durable_trainable import durable
 from ray.tune.schedulers import (TrialScheduler, FIFOScheduler,
                                  AsyncHyperBandScheduler)
 from ray.tune.stopper import MaximumIterationStopper, TrialPlateauStopper
+from ray.tune.sync_client import CommandBasedClient
 from ray.tune.trial import Trial
 from ray.tune.result import (TIMESTEPS_TOTAL, DONE, HOSTNAME, NODE_IP, PID,
                              EPISODES_TOTAL, TRAINING_ITERATION,
@@ -29,7 +30,7 @@ from ray.tune.result import (TIMESTEPS_TOTAL, DONE, HOSTNAME, NODE_IP, PID,
 from ray.tune.logger import Logger
 from ray.tune.experiment import Experiment
 from ray.tune.resources import Resources
-from ray.tune.suggest import grid_search
+from ray.tune.suggest import BasicVariantGenerator, grid_search
 from ray.tune.suggest.hyperopt import HyperOptSearch
 from ray.tune.suggest.ax import AxSearch
 from ray.tune.suggest._mock import _MockSuggestionAlgorithm
@@ -942,6 +943,58 @@ class TrainableFunctionApiTest(unittest.TestCase):
 
         self._testDurableTrainable(durable(test_train), function=True)
 
+    def testDurableTrainableSyncFunction(self):
+        """Check custom sync functions in durable trainables"""
+
+        class TestDurable(DurableTrainable):
+            def __init__(self, *args, **kwargs):
+                # Mock distutils.spawn.find_executable
+                # so `aws` command is found
+                import distutils.spawn
+                distutils.spawn.find_executable = lambda *_, **__: True
+                super(TestDurable, self).__init__(*args, **kwargs)
+
+            def check(self):
+                return bool(self.sync_function_tpl) and isinstance(
+                    self.storage_client, CommandBasedClient
+                ) and "aws" not in self.storage_client.sync_up_template
+
+        class TestTplDurable(TestDurable):
+            _sync_function_tpl = "echo static sync {source} {target}"
+
+        upload_dir = "s3://test-bucket/path"
+
+        def _create_remote_actor(trainable_cls, sync_to_cloud):
+            """Create a remote trainable actor from an experiment"""
+            exp = Experiment(
+                name="test_durable_sync",
+                run=trainable_cls,
+                sync_to_cloud=sync_to_cloud,
+                sync_to_driver=False,
+                upload_dir=upload_dir)
+
+            searchers = BasicVariantGenerator()
+            searchers.add_configurations([exp])
+            trial = searchers.next_trial()
+            cls = trial.get_trainable_cls()
+            actor = ray.remote(cls).remote(
+                remote_checkpoint_dir=upload_dir,
+                sync_function_tpl=trial.sync_to_cloud)
+            return actor
+
+        # This actor should create a default aws syncer, so check should fail
+        actor1 = _create_remote_actor(TestDurable, None)
+        self.assertFalse(ray.get(actor1.check.remote()))
+
+        # This actor should create a custom syncer, so check should pass
+        actor2 = _create_remote_actor(TestDurable,
+                                      "echo test sync {source} {target}")
+        self.assertTrue(ray.get(actor2.check.remote()))
+
+        # This actor should create a custom syncer, so check should pass
+        actor3 = _create_remote_actor(TestTplDurable, None)
+        self.assertTrue(ray.get(actor3.check.remote()))
+
     def testCheckpointDict(self):
         class TestTrain(Trainable):
             def setup(self, config):
diff --git a/python/ray/tune/tests/test_sync.py b/python/ray/tune/tests/test_sync.py
index 3675da055..bced13edb 100644
--- a/python/ray/tune/tests/test_sync.py
+++ b/python/ray/tune/tests/test_sync.py
@@ -1,5 +1,6 @@
 import glob
 import os
+import pickle
 import shutil
 import sys
 import tempfile
@@ -169,10 +170,16 @@ class TestSyncFunctionality(unittest.TestCase):
                 time.sleep(1)
                 tune.report(score=i)
 
-        mock = unittest.mock.Mock()
-
         def counter(local, remote):
-            mock()
+            count_file = os.path.join(tmpdir, "count.txt")
+            if not os.path.exists(count_file):
+                count = 0
+            else:
+                with open(count_file, "rb") as fp:
+                    count = pickle.load(fp)
+            count += 1
+            with open(count_file, "wb") as fp:
+                pickle.dump(count, fp)
 
         sync_config = tune.SyncConfig(
             upload_dir="test", sync_to_cloud=counter, cloud_sync_period=1)
@@ -191,7 +198,11 @@ class TestSyncFunctionality(unittest.TestCase):
             sync_config=sync_config,
         ).trials
 
-        self.assertEqual(mock.call_count, 12)
+        count_file = os.path.join(tmpdir, "count.txt")
+        with open(count_file, "rb") as fp:
+            count = pickle.load(fp)
+
+        self.assertEqual(count, 12)
         shutil.rmtree(tmpdir)
 
     def testClusterSyncFunction(self):
diff --git a/python/ray/tune/trial.py b/python/ray/tune/trial.py
index c27ffa1d8..60fb1ecab 100644
--- a/python/ray/tune/trial.py
+++ b/python/ray/tune/trial.py
@@ -187,6 +187,7 @@ class Trial:
                  placement_group_factory=None,
                  stopping_criterion=None,
                  remote_checkpoint_dir=None,
+                 sync_to_cloud=None,
                  checkpoint_freq=0,
                  checkpoint_at_end=False,
                  sync_on_checkpoint=True,
@@ -283,6 +284,7 @@ class Trial:
             self.remote_checkpoint_dir_prefix = remote_checkpoint_dir
         else:
             self.remote_checkpoint_dir_prefix = None
+        self.sync_to_cloud = sync_to_cloud
         self.checkpoint_freq = checkpoint_freq
         self.checkpoint_at_end = checkpoint_at_end
         self.keep_checkpoints_num = keep_checkpoints_num
diff --git a/python/ray/tune/tune.py b/python/ray/tune/tune.py
index f820c9394..a61bf6f00 100644
--- a/python/ray/tune/tune.py
+++ b/python/ray/tune/tune.py
@@ -397,6 +397,7 @@ def run(
                 local_dir=local_dir,
                 upload_dir=sync_config.upload_dir,
                 sync_to_driver=sync_config.sync_to_driver,
+                sync_to_cloud=sync_config.sync_to_cloud,
                 trial_name_creator=trial_name_creator,
                 trial_dirname_creator=trial_dirname_creator,
                 log_to_file=log_to_file,
diff --git a/python/ray/tune/utils/mock.py b/python/ray/tune/utils/mock.py
index 50de8868d..ca82a6244 100644
--- a/python/ray/tune/utils/mock.py
+++ b/python/ray/tune/utils/mock.py
@@ -65,7 +65,8 @@ class MockDurableTrainer(DurableTrainable, _MockTrainer):
     # TODO(ujvl): This class uses multiple inheritance; it should be cleaned
     #  up once the durable training API converges.
 
-    def __init__(self, remote_checkpoint_dir, *args, **kwargs):
+    def __init__(self, remote_checkpoint_dir, sync_function_tpl, *args,
+                 **kwargs):
         _MockTrainer.__init__(self, *args, **kwargs)
         DurableTrainable.__init__(self, remote_checkpoint_dir, *args, **kwargs)
 
diff --git a/python/ray/tune/utils/release_test_util.py b/python/ray/tune/utils/release_test_util.py
index 7c4074cb7..177b134ff 100644
--- a/python/ray/tune/utils/release_test_util.py
+++ b/python/ray/tune/utils/release_test_util.py
@@ -34,7 +34,11 @@ class ProgressCallback(tune.callback.Callback):
 
 
 class TestDurableTrainable(DurableTrainable):
-    def __init__(self, remote_checkpoint_dir, config, logger_creator=None):
+    def __init__(self,
+                 remote_checkpoint_dir,
+                 config,
+                 logger_creator=None,
+                 **kwargs):
         self.setup_env()
 
         super(TestDurableTrainable, self).__init__(