diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4eb78bf78..535b4c5c1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Add support for Model Access Control - Register, Update, Search and Delete by @rawwar in ([#332](https://github.com/opensearch-project/opensearch-py-ml/pull/332))
 - Add support for model connectors by @rawwar in ([#345](https://github.com/opensearch-project/opensearch-py-ml/pull/345))
 
+
 ### Changed
 - Modify ml-models.JenkinsFile so that it takes model format into account and can be triggered with generic webhook by @thanawan-atc in ([#211](https://github.com/opensearch-project/opensearch-py-ml/pull/211))
 - Update demo_tracing_model_torchscript_onnx.ipynb to use make_model_config_json by @thanawan-atc in ([#220](https://github.com/opensearch-project/opensearch-py-ml/pull/220))
@@ -44,6 +45,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Fix pandas dependency issue in nox session by installing pandas package to python directly by @thanawan-atc in ([#266](https://github.com/opensearch-project/opensearch-py-ml/pull/266))
 - Fix conditional job execution issue in model upload workflow by @thanawan-atc in ([#294](https://github.com/opensearch-project/opensearch-py-ml/pull/294))
 - fix bug in `MLCommonClient_client.upload_model` by @rawwar in ([#336](https://github.com/opensearch-project/opensearch-py-ml/pull/336))
+- Fix to ensure `model_id` is only required once when saving a model in `sentencetransformermodel.py` in ([#323](https://github.com/opensearch-project/opensearch-py-ml/pull/361))
 
 ## [1.1.0]
 
diff --git a/opensearch_py_ml/ml_models/sentencetransformermodel.py b/opensearch_py_ml/ml_models/sentencetransformermodel.py
index db5d5a226..ebee6899f 100644
--- a/opensearch_py_ml/ml_models/sentencetransformermodel.py
+++ b/opensearch_py_ml/ml_models/sentencetransformermodel.py
@@ -92,7 +92,7 @@ def __init__(
                 str("The default folder path already exists at : " + self.folder_path)
             )
 
-        self.model_id = model_id
+        self.model_id = model_id if model_id is not None else self.DEFAULT_MODEL_ID
         self.torch_script_zip_file_path = None
         self.onnx_zip_file_path = None
 
@@ -806,7 +806,7 @@ def save_as_pt(
         :rtype: string
         """
 
-        model = SentenceTransformer(model_id)
+        model = SentenceTransformer(self.model_id)
 
         if model_name is None:
             model_name = str(model_id.split("/")[-1] + ".pt")
diff --git a/tests/ml_models/test_sentencetransformermodel_pytest.py b/tests/ml_models/test_sentencetransformermodel_pytest.py
index c9c9046ba..493b79958 100644
--- a/tests/ml_models/test_sentencetransformermodel_pytest.py
+++ b/tests/ml_models/test_sentencetransformermodel_pytest.py
@@ -8,11 +8,13 @@
 import json
 import os
 import shutil
+from unittest.mock import MagicMock, patch
 from zipfile import ZipFile
 
 import pytest
 
-from opensearch_py_ml.ml_models import SentenceTransformerModel
+from opensearch_py_ml.ml_commons import MLCommonClient
+from opensearch_py_ml.ml_models.sentencetransformermodel import SentenceTransformerModel
 
 TEST_FOLDER = os.path.join(
     os.path.dirname(os.path.abspath("__file__")), "tests", "test_model_files"
@@ -658,5 +660,23 @@ def test_zip_model_with_license():
     clean_test_folder(TEST_FOLDER)
 
 
+@pytest.fixture
+def mock_opensearch_client():
+    with patch("opensearchpy.OpenSearch") as mock_client:
+        mock_client.return_value = MagicMock()
+        yield mock_client
+
+
+def test_opensearch_connection(mock_opensearch_client):
+    client = MLCommonClient(mock_opensearch_client)
+    assert client._client == mock_opensearch_client
+
+
+def test_init():
+    model = SentenceTransformerModel(model_id="test-model", folder_path="/test/folder")
+    assert model.folder_path == "/test/folder"
+    assert model.model_id == "test-model"
+
+
 clean_test_folder(TEST_FOLDER)
 clean_test_folder(TESTDATA_UNZIP_FOLDER)