diff --git a/awswrangler/redshift.py b/awswrangler/redshift.py
index 53b0b4159..323fb6216 100644
--- a/awswrangler/redshift.py
+++ b/awswrangler/redshift.py
@@ -869,7 +869,7 @@ def unload(
     sql: str,
     path: str,
     con: redshift_connector.Connection,
-    iam_role: Optional[str],
+    iam_role: Optional[str] = None,
     aws_access_key_id: Optional[str] = None,
     aws_secret_access_key: Optional[str] = None,
     aws_session_token: Optional[str] = None,
diff --git a/tests/test_redshift.py b/tests/test_redshift.py
index 23d23aa6f..340171f23 100644
--- a/tests/test_redshift.py
+++ b/tests/test_redshift.py
@@ -10,6 +10,7 @@
 import redshift_connector
 
 import awswrangler as wr
+from awswrangler import _utils
 
 from ._utils import dt, ensure_data_types, ensure_data_types_category, get_df, get_df_category, ts
 
@@ -776,3 +777,97 @@ def test_connect_secret_manager(dbname):
     df = wr.redshift.read_sql_query("SELECT 1", con=con)
     con.close()
     assert df.shape == (1, 1)
+
+
+def test_copy_unload_session(path, redshift_table):
+    df = pd.DataFrame({"col0": [1, 2, 3]})
+    con = wr.redshift.connect("aws-data-wrangler-redshift")
+    wr.redshift.copy(df=df, path=path, con=con, schema="public", table=redshift_table, mode="overwrite")
+    df2 = wr.redshift.unload(
+        sql=f"SELECT * FROM public.{redshift_table}",
+        con=con,
+        path=path,
+        keep_files=False,
+    )
+    assert df2.shape == (3, 1)
+    wr.redshift.copy(
+        df=df,
+        path=path,
+        con=con,
+        schema="public",
+        table=redshift_table,
+        mode="append",
+    )
+    df2 = wr.redshift.unload(
+        sql=f"SELECT * FROM public.{redshift_table}",
+        con=con,
+        path=path,
+        keep_files=False,
+    )
+    assert df2.shape == (6, 1)
+    dfs = wr.redshift.unload(
+        sql=f"SELECT * FROM public.{redshift_table}",
+        con=con,
+        path=path,
+        keep_files=False,
+        chunked=True,
+    )
+    for chunk in dfs:
+        assert len(chunk.columns) == 1
+    con.close()
+
+
+def test_copy_unload_creds(path, redshift_table):
+    credentials = _utils.get_credentials_from_session()
+    df = pd.DataFrame({"col0": [1, 2, 3]})
+    con = wr.redshift.connect("aws-data-wrangler-redshift")
+    wr.redshift.copy(
+        df=df,
+        path=path,
+        con=con,
+        schema="public",
+        table=redshift_table,
+        mode="overwrite",
+        aws_access_key_id=credentials.access_key,
+        aws_secret_access_key=credentials.secret_key,
+    )
+    df2 = wr.redshift.unload(
+        sql=f"SELECT * FROM public.{redshift_table}",
+        con=con,
+        path=path,
+        keep_files=False,
+        aws_access_key_id=credentials.access_key,
+        aws_secret_access_key=credentials.secret_key,
+    )
+    assert df2.shape == (3, 1)
+    wr.redshift.copy(
+        df=df,
+        path=path,
+        con=con,
+        schema="public",
+        table=redshift_table,
+        mode="append",
+        aws_access_key_id=credentials.access_key,
+        aws_secret_access_key=credentials.secret_key,
+    )
+    df2 = wr.redshift.unload(
+        sql=f"SELECT * FROM public.{redshift_table}",
+        con=con,
+        path=path,
+        keep_files=False,
+        aws_access_key_id=credentials.access_key,
+        aws_secret_access_key=credentials.secret_key,
+    )
+    assert df2.shape == (6, 1)
+    dfs = wr.redshift.unload(
+        sql=f"SELECT * FROM public.{redshift_table}",
+        con=con,
+        path=path,
+        keep_files=False,
+        chunked=True,
+        aws_access_key_id=credentials.access_key,
+        aws_secret_access_key=credentials.secret_key,
+    )
+    for chunk in dfs:
+        assert len(chunk.columns) == 1
+    con.close()