WordPress Multisite Change Main Site: A 15-Minute Step-by-Step Guide

Your WordPress multisite network has grown, but what happens when the main site no longer fits? It’s a frustrating spot to be in, especially when you realize there’s no official setting for this. We understand the challenge completely. 

That’s why we’ve laid out two methods for a successful WordPress multisite change main site process.

Let’s update your network’s foundation to match your new reality, safely.

TL;DR: Changing your multisite’s main site involves editing the wp-config.php file and running a careful database search-and-replace. Before you begin, always create a complete and verified copy of your entire network using a trusted backup plugin.

Prerequisites: Non-negotiable preparation

Before you touch a single file, we need to get everything in order. Skipping these steps is not an option if you want a safe and successful outcome. 

Secure a complete, verified WordPress backup. You need a full backup of your database and all your WordPress files. More importantly, you must test this backup by restoring it in a safe environment. An untested backup is just a hope. A verified backup is your undo button.

Replicate your network in a staging environment. Never perform this procedure on your live site first. Duplicate your entire network to a staging or development server. This is your sandbox. You can test, validate, and fix any mistakes here without any real-world consequences.

Gather critical site information. You’ll need the blog_id of the site you plan to promote. We’re using the Cloudways Database Manager for this guide, but the process is identical in any database manager. Just open the wp_blogs table to find the ID.

Prepare your database tools. A simple find-and-replace will corrupt your database. Use a specialized tool like the Better Search Replace plugin to do this safely.

WordPress Multisite change main site

With your preparation handled, you have two clear paths forward. The one you choose depends entirely on your goal.

1) Promoting a subsite to a primary site

This is the most common situation. You have an existing subsite, like one with blog_id 3, and you want it to be the new front door for your entire network.

Modify the constants in your wp-config.php file. This is the first step in telling WordPress about the change. Locate these constants and update them to reflect your new main site.

define('DOMAIN_CURRENT_SITE', 'newprimarydomain.com');

define('BLOG_ID_CURRENT_SITE', 3);

Update the core network database tables. Next, we need to update the network’s main records directly. Using a tool like phpMyAdmin or Adminer, you’ll make two precise changes. This is exactly why you have that full site backup ready. Be careful here, as you are editing fundamental tables.

Set the network’s new main address. Go into the wp_site table and change the domain to your new primary domain (newprimarydomain.com).

Make your subsite the new “front door.” Open the wp_blogs table, find the row for your chosen site (e.g., blog_id 3), and set its domain to newprimarydomain.com.

Retire the old main site’s domain. In that same wp_blogs table, find the original site (blog_id 1) and change its domain to something unique, like example-root.yournetwork.com. This step is crucial to avoid any conflicts.

Execute a network-wide search and replace. This is the final and most important step. Use your prepared tool to replace every instance of the old primary domain with newprimarydomain.com across all database tables. This corrects every stored URL in your content, settings, and media paths.

2) Changing the domain of the existing root site

This approach is for a simpler scenario. You are keeping blog_id 1 as your main site, but you’re changing its domain. This is common when moving a site from a development URL to its final production address.

Modify the wp-config.php file. You only need to update the domain itself. The blog ID for the main site remains 1.

define('DOMAIN_CURRENT_SITE', 'newproductiondomain.com'); 

// BLOG_ID_CURRENT_SITE remains 1

Update specific database tables. The new domain (newproductiondomain.com) needs to be changed in these five specific locations.

Execute a network-wide search and replace. Just like in the first method, run a full, serialization-safe search and replace to update all instances of the old domain to the new one.

Post-change verification protocol

Once the technical work is done, you must verify that it actually worked. This checklist will confirm the health of your network.

Best practices for a stable transition

These final steps ensure your network remains healthy and stable for the long term.

Parting thoughts

For most situations, the first option is the correct solution. It properly changes the network’s functional main site without trying to rewire its core structure.

However, this is an advanced procedure. It carries inherent risk because it affects your entire network. The process covers everything from creating a backup to the final verification. If any step is outside your technical confidence, we strongly recommend engaging a professional. This is a necessary and prudent investment to safeguard your network’s stability.

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