Hide Out of Stock Products in WooCommerce

You can hide out-of-stock products from catalog and search pages. The simplest way is through WooCommerce settings: WooCommerce > Settings > Products > Inventory > “Hide out of stock items from the catalog”. If you prefer a code-based approach, add to your functions.php. For more on managing stock in WooCommerce.

add_action( 'pre_get_posts', function( $query ) {
	if ( ! is_admin() && $query->is_main_query() && ( is_shop() || is_product_category() || is_product_tag() ) ) {
		$query->set( 'meta_query', array(
			array(
				'key'     => '_stock_status',
				'value'   => 'instock',
				'compare' => '=',
			),
		) );
	}
} );