diff --git a/blocks/edit_form.php b/blocks/edit_form.php
index 19624eb9ea0..ad32113fe0f 100644
--- a/blocks/edit_form.php
+++ b/blocks/edit_form.php
@@ -84,6 +84,12 @@ class block_edit_form extends moodleform {
         $weightoptions[$last] = get_string('bracketlast', 'block', $last);
 
         $regionoptions = $this->page->theme->get_all_block_regions();
+        foreach ($this->page->blocks->get_regions() as $region) {
+            // Make sure to add all custom regions of this particular page too.
+            if (!isset($regionoptions[$region])) {
+                $regionoptions[$region] = $region;
+            }
+        }
 
         $parentcontext = context::instance_by_id($this->block->instance->parentcontextid);
         $mform->addElement('hidden', 'bui_parentcontextid', $parentcontext->id);