switch_to_blog( int $new_blog_id, bool $deprecated = null )

Switch the current blog.

Description Description

This function is useful if you need to pull posts, or other information, from other blogs. You can switch back afterwards using restore_current_blog().

Things that aren’t switched:

  • plugins. See #14941

See also See also

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Parameters Parameters


(int) (Required) The ID of the blog to switch to. Default: current blog.


(bool) (Optional) Not used.

Default value: null

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Return Return

(true) Always returns true.

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Source Source

File: wp-includes/ms-blogs.php

function switch_to_blog( $new_blog_id, $deprecated = null ) {
	global $wpdb;

	$prev_blog_id = get_current_blog_id();
	if ( empty( $new_blog_id ) ) {
		$new_blog_id = $prev_blog_id;

	$GLOBALS['_wp_switched_stack'][] = $prev_blog_id;

	 * If we're switching to the same blog id that we're on,
	 * set the right vars, do the associated actions, but skip
	 * the extra unnecessary work
	if ( $new_blog_id == $prev_blog_id ) {
		 * Fires when the blog is switched.
		 * @since MU (3.0.0)
		 * @param int $new_blog_id  New blog ID.
		 * @param int $prev_blog_id Previous blog ID.
		do_action( 'switch_blog', $new_blog_id, $prev_blog_id );
		$GLOBALS['switched'] = true;
		return true;

	$wpdb->set_blog_id( $new_blog_id );
	$GLOBALS['table_prefix'] = $wpdb->get_blog_prefix();
	$GLOBALS['blog_id']      = $new_blog_id;

	if ( function_exists( 'wp_cache_switch_to_blog' ) ) {
		wp_cache_switch_to_blog( $new_blog_id );
	} else {
		global $wp_object_cache;

		if ( is_object( $wp_object_cache ) && isset( $wp_object_cache->global_groups ) ) {
			$global_groups = $wp_object_cache->global_groups;
		} else {
			$global_groups = false;

		if ( function_exists( 'wp_cache_add_global_groups' ) ) {
			if ( is_array( $global_groups ) ) {
				wp_cache_add_global_groups( $global_groups );
			} else {
				wp_cache_add_global_groups( array( 'users', 'userlogins', 'usermeta', 'user_meta', 'useremail', 'userslugs', 'site-transient', 'site-options', 'blog-lookup', 'blog-details', 'rss', 'global-posts', 'blog-id-cache', 'networks', 'sites', 'site-details', 'blog_meta' ) );
			wp_cache_add_non_persistent_groups( array( 'counts', 'plugins' ) );

	/** This filter is documented in wp-includes/ms-blogs.php */
	do_action( 'switch_blog', $new_blog_id, $prev_blog_id );
	$GLOBALS['switched'] = true;

	return true;

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Changelog Changelog

Version Description
MU (3.0.0) Introduced.

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User Contributed Notes User Contributed Notes

  1. Skip to note 2 content
    Contributed by Codex

    Multiple switches

    foreach( $blog_ids as $blog_id ){
        switch_to_blog( $blog_id );
        //Do stuff

    If you do not call restore_current_blog() after every switch_to_blog(), WordPress can get into a state that can potentially build the wrong urls for the site. See restore_current_blog() vs switch_to_blog().

  2. Skip to note 3 content


    Restores previous blog after a switch_to_blog call.

    Contrary to the function’s name, this does NOT restore the original blog but the previous blog. Calling `switch_to_blog()` twice in a row and then calling this function will result in being on the blog set by the first `switch_to_blog()` call.

  3. Skip to note 4 content
    Contributed by Brent Leavitt

    I was a little confused with the switch_to_blog() functionality when I first started using it. This function only affects the database which is being accessed on the network. I cannot access blocks of code, classes, functions, or variables that exist within a specific blog on the network. By extension, this also means that I cannot access themes or plugins that only exist on one site on the network. I was hoping for a little more power with this function before I realized that this was limited to site data being stored in the database.

    The following example does not work:

    Site 1 --> Site1_only_plugin --> Site1_only_plugin_function()

    That is, Site 1 has a unique plugin that has a bit of functionality that I want to access on Site 2 (or anywhere else on the network) without loading the full plugin to Site 2. I might be tempted to do something like this from Site 2:

    switch_to_blog( $site1 );
    $var = site1_only_plugin_function();

    This does not work. I can only use the switch_to_blog() functionality to access database values from other sites on the network. Here’s an example that does work:

    Site 1 --> Site1_only_plugin --> Site1_only_plugin_function()--> add_option( 'Site1_only_plugin_option', $var )

    The plugin on Site 1 has first set a value in the Site 1 database. I can then access that value in the options table from anywhere on the network as follows:

    switch_to_blog( $site1 );
    $var = get_option( 'Site1_only_plugin_option' );

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