Get all submissions from specific webform I am trying to load webform submissions by a particular webform sign_up.

Using Query webform submissions, this does get me all the IDs associated and I can load the data using 

$query = \Drupal::entityQuery('webform_submission')
  -&gt;condition('webform_id', 'sign_up');
$result = $query-&gt;execute(); // Gives me IDs associated with the "sign_up" webform.

$storage = \Drupal::entityTypeManager()-&gt;getStorage('webform_submission');
$submissions = $storage-&gt;loadMultiple($result);
$submission_data = array();
foreach ($submissions as $submission) {
  $submission_data[] = $submission-&gt;getData();
}
// $submission_data now contains all the submissions from "sign_up" webform.


Is this the correct way of getting the submissions? I would think Webform comes with some sort of API to query the submission results.

I also tried: https://www.drupal.org/project/webform/issues/2902682 but ended up with an empty array.
The Webform module stores submission data using a custom Entity-Attribute-Value model. Your example code is the easiest and fastest way to get all the submission data. The only limitation would be the number of submissions vs PHP's memory limit. You will run out of memory if you are loading 1000's submissions