Website migration: best practices for SEO

Website migrations are one of the highest-risk activities in digital marketing. Without a solid SEO strategy, backed by data such as user behaviour, keyword performance, and existing organic rankings, even the most well-designed site can lose traffic, rankings, and revenue after launch.

Whether you’re moving to a new platform, restructuring your website, or switching servers, every change impacts your existing SEO foundations. But with careful planning and execution, you can protect your hard-earned organic value… and even enhance it.

During a website migration, SEO matters

When launching a brand new website, you’re building from the ground up, and (hopefully) following our foundational SEO guidelines to maximise your efforts as early as possible. This process is all about identifying search opportunities, mapping keywords, and crafting a site architecture that’s as easy for customers to find and navigate as it is for Google to crawl and understand.

A website migration, on the other hand, involves significant alterations to your site’s technology, structure, design, or location. Here, we’re dealing with an existing digital ecosystem – comprising your rankings, traffic patterns, backlinks, internal links, and user expectations – often built up over years of hard work. And every change has consequences – many of which you might not even notice on the surface.

Common types of website migrations include:

• Platform changes – moving to a better content management system (CMS)

• Domain changes – renaming your domain during a rebrand

• Architecture updates – restructuring your site for better navigation

While these changes aim to improve user experience and brand credibility, they can disrupt search engine rankings if not prepared for and handled accordingly. Search engines need time to understand the updates, which often leads to short-term ranking drops. And if a migration isn’t executed properly, it can wipe out years of SEO value altogether.

But with an expert strategy (and support from website migration SEO services with proven results), it doesn’t have to be scary.

Your site migration SEO checklist

This isn’t just a case of changing everything based on new keyword research. Knowing how to migrate a website for SEO success requires a deep understanding of how these ecosystems work, so you can make strategic, data-driven decisions based on risks and rewards.

1. Prepare ahead of time

Successful migrations start long before the first change is implemented. Prep work is huge, and needs months (not weeks) to plan properly:

• Set clear objectives. What do you want to achieve? More traffic? Smoother UX? Higher conversions? Be specific and measurable with your goals for the migration.

• Benchmark current performance. Use tools like GA4, Google Search Console, Semrush, and Advanced Web Ranking to collect data on rankings, traffic patterns, and backlinks. This will help spot top-ranking pages, backlinks, and patterns worth preserving.

• Assemble your A-team. SEO experts, developers, designers – get everyone aligned from day one.

2. Test everything before going live

To catch any technical gremlins early, test everything in a staging environment before you go live:

• Create a staging site. This is a duplicate of your own website files and database on a subdomain (like staging.example.com, for instance). Keep this private, with a password, and no-index tags to stop search engines crawling the test version.

• Run thorough audits. Once you have your safe testing space, run your audits on tools such as Screaming Frog and have an SEO expert identify any major issues.

3. Map and manage your URLs

Redirects are non-negotiable if you want to keep your SEO gains intact.

• List every live URL. Crawl your current site and combine data from GA4, Google Search Console, your XML sitemap, and backlink reports.

• Plan redirects carefully. Use 301s (redirects) for pages with new equivalents. For outdated content without a replacement page, send users to the most relevant top-level page instead of sending users to random pages.

• Update internal links. Remove any internal links pointing to 404 pages. Don’t forget to check your sitemap, and other vital signposts for search engines (such as canonical tags, robots.txt, and hreflang tags), updating accordingly.

4. Check everything (again) pre-launch

Before launching, take time to catch anything you’ve missed:

• Run another pre-launch audit. This is a separate audit to make sure all the different potential issues are fully resolved.

• Test functionality across devices. For instance, checking broken menus or awkward layouts on mobile and fixing them.

• Check compliance. Are your privacy policy, cookie banners, and consent settings up to date with current legal standards?

• Make sure GA4 is tracking data. To stay on top of your website migration SEO impact​, you’ll want clean, uninterrupted data once you’re live.

5. Launch with eyes wide open

You’re ready to go live. But stay sharp.

• Back everything up. Your content, meta data, page templates – all of it.

• Migrate in stages if needed. For large sites, consider rolling things out in chunks (for instance, your product pages first, then blogs).

• Keep an eye on real-time data. Watch for errors, traffic drops, or spikes in your analytics as soon as you hit publish.

Monitoring post-website migration SEO impact​

The work doesn’t stop after launch. This stage is all about monitoring, learning, and adjusting where needed:

• Track everything. Use GA4 and Google Search Console to compare your site’s performance before and after the switch.

• Identify any issues. Look out for crawl errors, broken links, or redirect loops – and fix them fast.

• Submit updated sitemaps. Help search engines understand and index your new structure by clearly signalling what’s different.

• Monitor rankings. Keep an eye on keyword positions over the next few months. Organic visibility can dip temporarily, but you’ll want to catch any persistent issues early.

Real results: website migration SEO wins for Mizaic

Website migrations are high stakes for SEO, but offer high rewards when handled with precision. Our partnership with patient information management specialist Mizaic shows the power of our website migration SEO service​ (among others) in action. Previously IMMJ Systems, Mizaic needed to relaunch its rebrand back into the market with a website that would marry up.

To ensure a seamless website migration, our team diagnosed the issues carefully before prescribing our solution:

1. First, we built a future-focused, headless website for Mizaic, with keyword-led articles ready to go live with the site to support its performance.

2. Our migration strategy not only redirected traffic from the old IMMJ systems site, but also included the creation of new landing pages, paid search campaigns, and keyword-driven blogs designed to improve SEO performance and communicate the brand name.

3. We amplified our approach with Google PPC ad campaigns, a PR launch, and email marketing to help push the new brand and product terms into the market, ensuring a seamless transition.

Within just four months, brand searches for the new name surpassed those for the old. Branded search volume saw an 87% year-on-year increase, organic traffic surged by 105%, and conversion rates rose by 141%. We secured national media coverage for Mizaic, and our gated content successfully attracted qualified NHS leads.

Partnering with an experienced, full-service agency like The Bigger Boat ensures every step – from planning your migration and writing updated content to monitoring and fixing any issues – is at the hands of an integrated team of experts, working together to make sure you get the best out of your budget, from one point of contact.