diff --git a/datashuttle/utils/formatting.py b/datashuttle/utils/formatting.py
index 8c32ac48..cc653f0d 100644
--- a/datashuttle/utils/formatting.py
+++ b/datashuttle/utils/formatting.py
@@ -216,26 +216,28 @@ def update_names_with_datetime(names: List[str]) -> None:
     Format using key-value pair for bids, i.e. date-20221223_time-
     """
     date = str(datetime.datetime.now().date().strftime("%Y%m%d"))
-    format_date = f"date-{date}"
+    date_with_key = f"date-{date}"
 
     time_ = datetime.datetime.now().time().strftime("%H%M%S")
-    format_time = f"time-{time_}"
+    time_with_key = f"time-{time_}"
+
+    datetime_with_key = f"datetime-{date}T{time_}"
 
     for i, name in enumerate(names):
-        if tags("datetime") in name:  # must come first
+        # datetime conditional must come first.
+        if tags("datetime") in name:
             name = add_underscore_before_after_if_not_there(
                 name, tags("datetime")
             )
-            datetime_ = f"{format_date}_{format_time}"
-            names[i] = name.replace(tags("datetime"), datetime_)
+            names[i] = name.replace(tags("datetime"), datetime_with_key)
 
         elif tags("date") in name:
             name = add_underscore_before_after_if_not_there(name, tags("date"))
-            names[i] = name.replace(tags("date"), format_date)
+            names[i] = name.replace(tags("date"), date_with_key)
 
         elif tags("time") in name:
             name = add_underscore_before_after_if_not_there(name, tags("time"))
-            names[i] = name.replace(tags("time"), format_time)
+            names[i] = name.replace(tags("time"), time_with_key)
 
 
 def add_underscore_before_after_if_not_there(string: str, key: str) -> str:
diff --git a/docs/source/conf.py b/docs/source/conf.py
index 2b58a585..9a21f6d1 100644
--- a/docs/source/conf.py
+++ b/docs/source/conf.py
@@ -114,7 +114,7 @@
 
 html_favicon = "_static/logo_light.png"
 
-# Cutomize the theme
+# Customize the theme
 html_theme_options = {
     "icon_links": [
         {
diff --git a/tests/tests_integration/test_command_line_interface.py b/tests/tests_integration/test_command_line_interface.py
index d087d932..4180a764 100644
--- a/tests/tests_integration/test_command_line_interface.py
+++ b/tests/tests_integration/test_command_line_interface.py
@@ -611,7 +611,7 @@ def convert_kwargs_to_cli(self, kwargs, sep="-"):
         Take a list of key-value pairs that make up
         the arguments we want to pass to CLI, and
         put them in correct format. This involves
-        pre-pending "--argument_name" for non-positional
+        prepending "--argument_name" for non-positional
         arguments, and wrapping paths in quotes.
         """
         positionals = ["local_path", "central_path", "connection_method"]
diff --git a/tests/tests_integration/test_filesystem_transfer.py b/tests/tests_integration/test_filesystem_transfer.py
index d13d04fc..9685886c 100644
--- a/tests/tests_integration/test_filesystem_transfer.py
+++ b/tests/tests_integration/test_filesystem_transfer.py
@@ -318,7 +318,7 @@ def test_transfer_with_keyword_parameters(
                     (base_local / "rawdata" / sub / "ses*").as_posix()
                 )
 
-                datetime_regexp = r"date-\d\d\d\d\d\d\d\d_time-\d\d\d\d\d\d"
+                datetime_regexp = "datetime-\d{8}T\d{6}"
 
                 assert re.match(
                     "ses-001_" + datetime_regexp, sessions_in_path[0]
diff --git a/tests/tests_integration/test_make_folders.py b/tests/tests_integration/test_make_folders.py
index e3c37a26..9247adce 100644
--- a/tests/tests_integration/test_make_folders.py
+++ b/tests/tests_integration/test_make_folders.py
@@ -317,8 +317,8 @@ def test_datetime_flag_in_session(self, project):
         )
 
         # Convert the minutes to regexp as could change during test runtime
-        regexp_time = r"\d\d\d\d\d\d"
-        datetime_regexp = f"{date}_time-{regexp_time}"
+        regexp_time = r"\d{6}"
+        datetime_regexp = f"datetime-{date}T{regexp_time}"
 
         assert all([re.search(datetime_regexp, name) for name in ses_names])
         assert all([tags("time") not in name for name in ses_names])
diff --git a/tests/tests_unit/test_unit.py b/tests/tests_unit/test_unit.py
index 25f5288e..dd9fe5a3 100644
--- a/tests/tests_unit/test_unit.py
+++ b/tests/tests_unit/test_unit.py
@@ -23,6 +23,8 @@ def test_datetime_string_replacement(self, key, underscore_position):
         keywords with the date / time / datetime. Also, it will
         pre/append underscores to the tags if they are not
         already there (e.g if user input "sub-001@DATE").
+        Note cannot use regex \d{8} format because we are in an
+        f-string.
         """
         start = "sub-001"
         end = "other-tag"
@@ -34,13 +36,15 @@ def test_datetime_string_replacement(self, key, underscore_position):
             regex = re.compile(rf"{start}_time-\d\d\d\d\d\d_{end}")
         elif key == tags("datetime"):
             regex = re.compile(
-                rf"{start}_date-\d\d\d\d\d\d\d\d_time-\d\d\d\d\d\d_{end}"
+                rf"{start}_datetime-\d\d\d\d\d\d\d\dT\d\d\d\d\d\d_{end}"
             )
 
         name_list = [name]
         formatting.update_names_with_datetime(name_list)
 
-        assert re.search(regex, name_list[0]) is not None
+        assert (
+            re.search(regex, name_list[0]) is not None
+        ), "datetime formatting is incorrect."
 
     @pytest.mark.parametrize(
         "prefix_and_names",