diff --git a/core/modules/field/src/Plugin/migrate/source/d7/FieldInstance.php b/core/modules/field/src/Plugin/migrate/source/d7/FieldInstance.php
index a5fb4d4..46b6e29 100644
--- a/core/modules/field/src/Plugin/migrate/source/d7/FieldInstance.php
+++ b/core/modules/field/src/Plugin/migrate/source/d7/FieldInstance.php
@@ -8,6 +8,11 @@
 /**
  * Drupal 7 field instances source from database.
  *
+ * @internal
+ *
+ * This class is marked as internal and should not be extended. Use
+ * Drupal\migrate_drupal\Plugin\migrate\source\DrupalSqlBase instead.
+ *
  * @MigrateSource(
  *   id = "d7_field_instance",
  *   source_provider = "field"
@@ -43,6 +48,28 @@ public function query() {
   /**
    * {@inheritdoc}
    */
+  protected function initializeIterator() {
+    $results = $this->prepareQuery()->execute()->fetchAll();
+
+    // Group all instances by their base field.
+    $instances = [];
+    foreach ($results as $result) {
+      $instances[$result['field_id']][] = $result;
+    }
+
+    // Add the array of all instances using the same base field to each row.
+    $rows = [];
+    foreach ($results as $result) {
+      $result['instances'] = $instances[$result['field_id']];
+      $rows[] = $result;
+    }
+
+    return new \ArrayIterator($rows);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
   public function fields() {
     return [
       'id' => $this->t('The field instance ID.'),
diff --git a/core/modules/field/tests/src/Kernel/Plugin/migrate/source/d7/FieldInstanceTest.php b/core/modules/field/tests/src/Kernel/Plugin/migrate/source/d7/FieldInstanceTest.php
index e08f0b0..895fe3f 100644
--- a/core/modules/field/tests/src/Kernel/Plugin/migrate/source/d7/FieldInstanceTest.php
+++ b/core/modules/field/tests/src/Kernel/Plugin/migrate/source/d7/FieldInstanceTest.php
@@ -68,6 +68,7 @@ public function providerSource() {
         'bundle' => 'page',
         'data' => 'a:6:{s:5:"label";s:4:"Body";s:6:"widget";a:4:{s:4:"type";s:26:"text_textarea_with_summary";s:8:"settings";a:2:{s:4:"rows";i:20;s:12:"summary_rows";i:5;}s:6:"weight";i:-4;s:6:"module";s:4:"text";}s:8:"settings";a:3:{s:15:"display_summary";b:1;s:15:"text_processing";i:1;s:18:"user_register_form";b:0;}s:7:"display";a:2:{s:7:"default";a:5:{s:5:"label";s:6:"hidden";s:4:"type";s:12:"text_default";s:8:"settings";a:0:{}s:6:"module";s:4:"text";s:6:"weight";i:0;}s:6:"teaser";a:5:{s:5:"label";s:6:"hidden";s:4:"type";s:23:"text_summary_or_trimmed";s:8:"settings";a:1:{s:11:"trim_length";i:600;}s:6:"module";s:4:"text";s:6:"weight";i:0;}}s:8:"required";b:0;s:11:"description";s:0:"";}',
         'deleted' => '0',
+        'type' => 'text_with_summary',
         'label' => 'Body',
         'widget' => [
           'type' => 'text_textarea_with_summary',
@@ -118,6 +119,18 @@ public function providerSource() {
           'translatable' => '0',
           'deleted' => '0',
         ],
+        'instances' => [
+          [
+            'id' => '2',
+            'field_id' => '2',
+            'field_name' => 'body',
+            'entity_type' => 'node',
+            'bundle' => 'page',
+            'data' => 'a:6:{s:5:"label";s:4:"Body";s:6:"widget";a:4:{s:4:"type";s:26:"text_textarea_with_summary";s:8:"settings";a:2:{s:4:"rows";i:20;s:12:"summary_rows";i:5;}s:6:"weight";i:-4;s:6:"module";s:4:"text";}s:8:"settings";a:3:{s:15:"display_summary";b:1;s:15:"text_processing";i:1;s:18:"user_register_form";b:0;}s:7:"display";a:2:{s:7:"default";a:5:{s:5:"label";s:6:"hidden";s:4:"type";s:12:"text_default";s:8:"settings";a:0:{}s:6:"module";s:4:"text";s:6:"weight";i:0;}s:6:"teaser";a:5:{s:5:"label";s:6:"hidden";s:4:"type";s:23:"text_summary_or_trimmed";s:8:"settings";a:1:{s:11:"trim_length";i:600;}s:6:"module";s:4:"text";s:6:"weight";i:0;}}s:8:"required";b:0;s:11:"description";s:0:"";}',
+            'deleted' => '0',
+            'type' => 'text_with_summary',
+          ],
+        ],
       ],
     ];