Disable Comments in WordPress Completely Without a Plugin

If a WordPress site has no blog, comments only attract spam. To disable comments in WordPress completely without a plugin, you have to switch them off in several places: post type support, the open/closed check, existing comments, block theme templates and the admin screens. This snippet covers all of them in one code block.

The snippet

<?php
/**
 * Disable comments everywhere: front end, block themes, REST, XML-RPC and wp-admin.
 */

// Remove comment and trackback support from every post type.
add_action( 'init', 'dpc_remove_comment_support', 100 );
function dpc_remove_comment_support(): void {
	foreach ( get_post_types() as $post_type ) {
		if ( post_type_supports( $post_type, 'comments' ) ) {
			remove_post_type_support( $post_type, 'comments' );
			remove_post_type_support( $post_type, 'trackbacks' );
		}
	}
}

// Close comments and pings. Forms, wp-comments-post.php, REST and pingbacks all check these.
add_filter( 'comments_open', '__return_false', 20 );
add_filter( 'pings_open', '__return_false', 20 );

// Hide existing comments and counts.
add_filter( 'comments_array', '__return_empty_array', 20 );
add_filter( 'get_comments_number', '__return_zero', 20 );

// Block themes query comments directly, so empty the comment blocks.
foreach ( array( 'core/comments', 'core/post-comments-form', 'core/post-comments-count', 'core/post-comments-link', 'core/latest-comments' ) as $dpc_block ) {
	add_filter( "render_block_{$dpc_block}", '__return_empty_string' );
}
unset( $dpc_block );

// No comments feed link, no Recent Comments widget.
add_filter( 'feed_links_show_comments_feed', '__return_false' );
add_action( 'widgets_init', 'dpc_unregister_comments_widget' );
function dpc_unregister_comments_widget(): void {
	unregister_widget( 'WP_Widget_Recent_Comments' );
}

// wp-admin: menu, screens and admin bar.
add_action( 'admin_menu', 'dpc_remove_comments_menu' );
function dpc_remove_comments_menu(): void {
	remove_menu_page( 'edit-comments.php' );
}

add_action( 'load-edit-comments.php', 'dpc_redirect_comments_screen' );
add_action( 'load-comment.php', 'dpc_redirect_comments_screen' );
function dpc_redirect_comments_screen(): void {
	wp_safe_redirect( admin_url() );
	exit;
}

add_action( 'admin_bar_menu', 'dpc_remove_comments_admin_bar', 999 );
function dpc_remove_comments_admin_bar( WP_Admin_Bar $admin_bar ): void {
	$admin_bar->remove_node( 'comments' );
}

How it works

Post types: on init at priority 100, after themes and plugins have registered their post types, comment and trackback support is removed, so the Discussion panel disappears from the editor.
Open or closed: comments_open and pings_open return false. WordPress checks these before it shows a form, before it accepts a comment through wp-comments-post.php or the REST API, and before it accepts a pingback.
Existing comments: comments_array is emptied for classic themes, and get_comments_number returns 0, so “3 Comments” links and counts disappear.
Block themes: the Comments, Comments Form, Comments Count, Comments Link and Latest Comments blocks render as empty strings, because block themes query comments directly instead of going through comments_array.
wp-admin: the Comments menu is removed, direct visits to edit-comments.php and comment.php redirect to the Dashboard, and the admin bar bubble, the Recent Comments widget and the comments feed link are gone.

Compared with the older One-Click Import version: support is removed on init instead of admin_init, so it also applies on the front end; the redirect uses load-{page} hooks and wp_safe_redirect(); block themes are covered; every function has the dpc_ prefix; and the removal of dashboard_recent_comments, a widget WordPress no longer has, is dropped.

Add it with Scripts Organizer

In Scripts Organizer go to Code Blocks → Add New and give the block a name. Set Trigger location to Everywhere, tick PHP under Script location, paste the code into the PHP editor and publish. Leave Action/Hook empty. Everywhere matters here: the code must run in wp-admin for the menus, on the front end for the templates, and in REST and wp-comments-post.php requests, which neither Admin only nor Conditions code reaches.

The same code also works unchanged in a small plugin or an mu-plugin.

Customise it

Keep WooCommerce reviews (they are comments of type review): in dpc_remove_comment_support() skip 'product', and replace the two __return_false filters with a function that returns false unless get_post_type( $post_id ) is 'product'.
Delete old comments for good: empty them in Comments before you enable the snippet, or run wp comment delete $(wp comment list --format=ids) --force with WP-CLI.

Gotchas

Comments are hidden, not deleted. Disable the code block and they come back.
The Activity box on the Dashboard can still list comments that already exist.
WooCommerce product reviews are comments too, so they are closed and hidden unless you apply the customisation above.
Don’t expect a measurable speed gain; the benefit is no spam and a cleaner admin.

In the Scripts Organizer library Import it with one click from Scripts Organizer.