diff --git a/manilaclient/tests/functional/osc/test_share_instances.py b/manilaclient/tests/functional/osc/test_share_instances.py
new file mode 100644
index 000000000..b867e4de6
--- /dev/null
+++ b/manilaclient/tests/functional/osc/test_share_instances.py
@@ -0,0 +1,101 @@
+#   Licensed under the Apache License, Version 2.0 (the "License"); you may
+#   not use this file except in compliance with the License. You may obtain
+#   a copy of the License at
+#
+#        http://www.apache.org/licenses/LICENSE-2.0
+#
+#   Unless required by applicable law or agreed to in writing, software
+#   distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#   WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#   License for the specific language governing permissions and limitations
+#   under the License.
+
+from tempest.lib import exceptions
+
+from manilaclient.tests.functional.osc import base
+
+
+class ShareInstancesCLITest(base.OSCClientTestBase):
+    def setUp(self):
+        super().setUp()
+        # Create a share to test with
+        self.share = self.create_share()
+        # Get share instances for testing
+        self.share_instances = self.listing_result('share instance', 'list')
+        self.share_instance = (
+            self.share_instances[0] if self.share_instances else None
+        )
+        self.non_existent_id = '76a7dd8e-7564-41d4-a184-06dc20e13d7a'
+        self.invalid_id = 'invalid-format'
+
+    def test_share_instance_list(self):
+        # Test basic listing
+        instances = self.listing_result('share instance', 'list')
+        self.assertTableStruct(
+            instances,
+            [
+                'ID',
+                'Share ID',
+                'Host',
+                'Status',
+                'Availability Zone',
+                'Share Network ID',
+                'Share Server ID',
+                'Share Type ID',
+            ],
+        )
+
+    def test_share_instance_show(self):
+        result = self.dict_result(
+            'share instance', f'show {self.share_instance["ID"]}'
+        )
+        self.assertEqual(self.share_instance['ID'], result['id'])
+
+    def test_share_instance_delete_non_existent(self):
+        self.assertRaises(
+            exceptions.CommandFailed,
+            self.openstack,
+            f'share instance delete {self.non_existent_id}',
+        )
+
+    def test_share_instance_set_non_existent(self):
+        self.assertRaises(
+            exceptions.CommandFailed,
+            self.openstack,
+            f'share instance set {self.non_existent_id}  --status available',
+        )
+
+    def test_share_instance_set_invalid_status(self):
+        self.assertRaises(
+            exceptions.CommandFailed,
+            self.openstack,
+            f'share instance set {self.invalid_id} --status available',
+        )
+
+    def test_share_instance_show_non_existent(self):
+        self.assertRaises(
+            exceptions.CommandFailed,
+            self.openstack,
+            f'share instance show {self.non_existent_id}',
+        )
+
+    def test_share_instance_show_invalid_id_format(self):
+        self.assertRaises(
+            exceptions.CommandFailed,
+            self.openstack,
+            f'share instance show {self.invalid_id}',
+        )
+
+    def test_share_instance_list_invalid_filter_share_id_format(self):
+        self.assertRaises(
+            exceptions.CommandFailed,
+            self.openstack,
+            f'share instance list --share {self.invalid_id}',
+        )
+
+    def test_share_instance_list_invalid_filter_non_existent(self):
+        self.assertRaises(
+            exceptions.CommandFailed,
+            self.openstack,
+            f'share instance list --share {self.non_existent_id}',
+        )