diff --git a/scene/3d/node_3d.cpp b/scene/3d/node_3d.cpp
index 112816c045e..41aba9ef227 100644
--- a/scene/3d/node_3d.cpp
+++ b/scene/3d/node_3d.cpp
@@ -108,12 +108,15 @@ void Node3D::_propagate_transform_changed(Node3D *p_origin) {
 		return;
 	}
 
-	for (Node3D *&E : data.children) {
-		if (E->data.top_level) {
-			continue; //don't propagate to a top_level
+	for (uint32_t n = 0; n < data.node3d_children.size(); n++) {
+		Node3D *s = data.node3d_children[n];
+
+		// Don't propagate to a toplevel.
+		if (!s->data.top_level) {
+			s->_propagate_transform_changed(p_origin);
 		}
-		E->_propagate_transform_changed(p_origin);
 	}
+
 #ifdef TOOLS_ENABLED
 	if ((!data.gizmos.is_empty() || data.notify_transform) && !data.ignore_notification && !xform_change.in_list()) {
 #else
@@ -148,9 +151,11 @@ void Node3D::_notification(int p_what) {
 			}
 
 			if (data.parent) {
-				data.C = data.parent->data.children.push_back(this);
-			} else {
-				data.C = nullptr;
+				data.index_in_parent = data.parent->data.node3d_children.size();
+				data.parent->data.node3d_children.push_back(this);
+			} else if (data.index_in_parent != UINT32_MAX) {
+				data.index_in_parent = UINT32_MAX;
+				ERR_PRINT("Node3D ENTER_TREE detected without EXIT_TREE, recovering.");
 			}
 
 			if (data.top_level && !Engine::get_singleton()->is_editor_hint()) {
@@ -202,11 +207,27 @@ void Node3D::_notification(int p_what) {
 			if (xform_change.in_list()) {
 				get_tree()->xform_change_list.remove(&xform_change);
 			}
-			if (data.C) {
-				data.parent->data.children.erase(data.C);
+
+			if (data.parent) {
+				if (data.index_in_parent != UINT32_MAX) {
+					// Aliases
+					uint32_t c = data.index_in_parent;
+					LocalVector<Node3D *> &parent_children = data.parent->data.node3d_children;
+
+					parent_children.remove_at_unordered(c);
+
+					// After unordered remove, we need to inform the moved child
+					// what their new id is in the parent children list.
+					if (parent_children.size() > c) {
+						parent_children[c]->data.index_in_parent = c;
+					}
+				} else {
+					ERR_PRINT("Node3D index_in_parent unset at EXIT_TREE.");
+				}
 			}
+			data.index_in_parent = UINT32_MAX;
+
 			data.parent = nullptr;
-			data.C = nullptr;
 			_update_visibility_parent(true);
 			_disable_client_physics_interpolation();
 		} break;
@@ -1063,11 +1084,12 @@ void Node3D::_propagate_visibility_changed() {
 	}
 #endif
 
-	for (Node3D *c : data.children) {
-		if (!c || !c->data.visible) {
-			continue;
+	for (uint32_t n = 0; n < data.node3d_children.size(); n++) {
+		Node3D *s = data.node3d_children[n];
+
+		if (s->data.visible) {
+			s->_propagate_visibility_changed();
 		}
-		c->_propagate_visibility_changed();
 	}
 }
 
@@ -1312,7 +1334,7 @@ void Node3D::_update_visibility_parent(bool p_update_root) {
 		RS::get_singleton()->instance_set_visibility_parent(vi->get_instance(), data.visibility_parent);
 	}
 
-	for (Node3D *c : data.children) {
+	for (Node3D *c : data.node3d_children) {
 		c->_update_visibility_parent(false);
 	}
 }
diff --git a/scene/3d/node_3d.h b/scene/3d/node_3d.h
index 930a174136d..8d09872c91f 100644
--- a/scene/3d/node_3d.h
+++ b/scene/3d/node_3d.h
@@ -153,8 +153,12 @@ private:
 		RID visibility_parent;
 
 		Node3D *parent = nullptr;
-		List<Node3D *> children;
-		List<Node3D *>::Element *C = nullptr;
+
+		// An unordered vector of `Spatial` children only.
+		// This is a subset of the `Node::children`, purely
+		// an optimization for faster traversal.
+		LocalVector<Node3D *> node3d_children;
+		uint32_t index_in_parent = UINT32_MAX;
 
 		ClientPhysicsInterpolationData *client_physics_interpolation_data = nullptr;
 
diff --git a/scene/main/canvas_item.cpp b/scene/main/canvas_item.cpp
index 1aa2d964eda..f5f7e5b036e 100644
--- a/scene/main/canvas_item.cpp
+++ b/scene/main/canvas_item.cpp
@@ -317,8 +317,15 @@ void CanvasItem::_notification(int p_what) {
 
 				if (ci) {
 					parent_visible_in_tree = ci->is_visible_in_tree();
-					C = ci->children_items.push_back(this);
+
+					data.index_in_parent = ci->data.canvas_item_children.size();
+					ci->data.canvas_item_children.push_back(this);
 				} else {
+					if (data.index_in_parent != UINT32_MAX) {
+						data.index_in_parent = UINT32_MAX;
+						ERR_PRINT("CanvasItem ENTER_TREE detected without EXIT_TREE, recovering.");
+					}
+
 					CanvasLayer *cl = Object::cast_to<CanvasLayer>(parent);
 
 					if (cl) {
@@ -388,10 +395,27 @@ void CanvasItem::_notification(int p_what) {
 				get_tree()->xform_change_list.remove(&xform_change);
 			}
 			_exit_canvas();
-			if (C) {
-				Object::cast_to<CanvasItem>(get_parent())->children_items.erase(C);
-				C = nullptr;
+
+			CanvasItem *parent = Object::cast_to<CanvasItem>(get_parent());
+			if (parent) {
+				if (data.index_in_parent != UINT32_MAX) {
+					// Aliases
+					uint32_t c = data.index_in_parent;
+					LocalVector<CanvasItem *> &parent_children = parent->data.canvas_item_children;
+
+					parent_children.remove_at_unordered(c);
+
+					// After unordered remove, we need to inform the moved child
+					// what their new id is in the parent children list.
+					if (parent_children.size() > c) {
+						parent_children[c]->data.index_in_parent = c;
+					}
+				} else {
+					ERR_PRINT("CanvasItem index_in_parent unset at EXIT_TREE.");
+				}
 			}
+			data.index_in_parent = UINT32_MAX;
+
 			if (window) {
 				window->disconnect(SceneStringName(visibility_changed), callable_mp(this, &CanvasItem::_window_visibility_changed));
 				window = nullptr;
@@ -1056,11 +1080,11 @@ void CanvasItem::_notify_transform(CanvasItem *p_node) {
 		}
 	}
 
-	for (CanvasItem *ci : p_node->children_items) {
-		if (ci->top_level) {
-			continue;
+	for (uint32_t n = 0; n < p_node->data.canvas_item_children.size(); n++) {
+		CanvasItem *ci = p_node->data.canvas_item_children[n];
+		if (!ci->top_level) {
+			_notify_transform(ci);
 		}
-		_notify_transform(ci);
 	}
 }
 
@@ -1611,9 +1635,11 @@ void CanvasItem::_update_texture_filter_changed(bool p_propagate) {
 	_update_self_texture_filter(texture_filter_cache);
 
 	if (p_propagate) {
-		for (CanvasItem *E : children_items) {
-			if (!E->top_level && E->texture_filter == TEXTURE_FILTER_PARENT_NODE) {
-				E->_update_texture_filter_changed(true);
+		for (uint32_t n = 0; n < data.canvas_item_children.size(); n++) {
+			CanvasItem *ci = data.canvas_item_children[n];
+
+			if (!ci->top_level && ci->texture_filter == TEXTURE_FILTER_PARENT_NODE) {
+				ci->_update_texture_filter_changed(true);
 			}
 		}
 	}
@@ -1665,9 +1691,10 @@ void CanvasItem::_update_texture_repeat_changed(bool p_propagate) {
 	_update_self_texture_repeat(texture_repeat_cache);
 
 	if (p_propagate) {
-		for (CanvasItem *E : children_items) {
-			if (!E->top_level && E->texture_repeat == TEXTURE_REPEAT_PARENT_NODE) {
-				E->_update_texture_repeat_changed(true);
+		for (uint32_t n = 0; n < data.canvas_item_children.size(); n++) {
+			CanvasItem *ci = data.canvas_item_children[n];
+			if (!ci->top_level && ci->texture_repeat == TEXTURE_REPEAT_PARENT_NODE) {
+				ci->_update_texture_repeat_changed(true);
 			}
 		}
 	}
diff --git a/scene/main/canvas_item.h b/scene/main/canvas_item.h
index 14e11a97686..9de847b81fc 100644
--- a/scene/main/canvas_item.h
+++ b/scene/main/canvas_item.h
@@ -83,8 +83,13 @@ private:
 	Color modulate = Color(1, 1, 1, 1);
 	Color self_modulate = Color(1, 1, 1, 1);
 
-	List<CanvasItem *> children_items;
-	List<CanvasItem *>::Element *C = nullptr;
+	struct Data {
+		// An unordered vector of `CanvasItem` children only.
+		// This is a subset of the `Node::children`, purely
+		// an optimization for faster traversal.
+		LocalVector<CanvasItem *> canvas_item_children;
+		uint32_t index_in_parent = UINT32_MAX;
+	} data;
 
 	int light_mask = 1;
 	uint32_t visibility_layer = 1;