Website Migration SEO: How to Protect Your Rankings

Key Takeaways

• A migration done without proper SEO planning can cost you organic traffic in the weeks after launch. Most of the usual causes (missing redirects, cut content, broken internal links) are preventable with the right process. Google says visibility "may fluctuate temporarily during the move", so some movement is normal even when it is done well.
• Google recommends implementing 301 redirects for every changed URL and keeping them in place for as long as possible, generally at least a year — Google Search Central: Site Move Guide.
• Losing backlinks during a migration is one of the most damaging and commonly overlooked issues — tools like Ahrefs or Semrush let you audit your backlink profile before you go live.
• Post-migration, Search Console's Page indexing and Performance reports are your most important early-warning systems. Our rule of thumb is to check them daily for the first two weeks.

Why Website Migrations Go Wrong

Every few years, a business outgrows its website. Maybe the platform no longer serves the business, the design is outdated, or the company has rebranded entirely. Whatever the reason, the decision to migrate to a new website is usually the right one — but the execution is where things go badly wrong.

The core problem is that many businesses treat a website migration as purely a design or development project. The old site gets rebuilt, the new one goes live, and everyone congratulates themselves on the shiny new design — until the Google Analytics dashboard turns red and organic traffic drops.

Website migration SEO failures are remarkably common. URL structures change without redirects. Content gets cut without replacement. Internal linking is rebuilt from scratch without thought for authority flow. The result can be a long, slow recovery.

This guide covers everything you need to do before, during, and after a website migration to protect your organic visibility — and what to do if things do go wrong.

What Counts as a Website Migration?

Not all migrations are equal. In SEO terms, a migration is any change that significantly affects how search engines crawl, index, or rank your website. That includes:

• Platform changes — moving from WordPress to Webflow, Shopify, a custom build, or any other CMS
• Domain changes — rebranding and moving from oldcompany.com to newcompany.co.uk
• URL restructure — changing your URL patterns (e.g., from /category/product/ to /product/)
• HTTP to HTTPS — though this is now baseline, older sites still go through this
• Redesign with structural changes — new navigation, removed pages, changed content hierarchy

Each of these carries SEO risk. The more changes happening simultaneously, the higher the risk — and the harder it becomes to diagnose problems afterwards.

Pre-Migration: The SEO Groundwork

What Should You Audit Before Migrating?

Before a single line of new code goes live, you need a clear picture of what you're protecting. A thorough pre-migration audit should cover:

1. Crawl the existing site Use Screaming Frog SEO Spider (the free version crawls up to 500 URLs) or a similar crawler to capture every URL on your current site. Export the full list — this becomes your redirect mapping document.

2. Identify your top-performing pages In Google Search Console, go to the Performance report and filter by page. Sort by clicks, then by impressions. Your top 20–30 pages are your priority assets — these must be protected at all costs during migration.

3. Audit your backlink profile Export your backlink data from Ahrefs, Semrush, or Google Search Console's Links report. Document which URLs have the most inbound links. These are the pages where a missing redirect causes the most damage — you lose the link equity that took years to build.

4. Document your keyword rankings Take a snapshot of your current rankings using a rank tracking tool. This gives you a baseline to measure against post-launch. Without this, you won't be able to tell whether traffic drops are migration-related or seasonal.

5. Benchmark your Core Web Vitals Run your current site through Google PageSpeed Insights and note your LCP, CLS and INP scores. The new site should improve on these, not worsen them. For a deeper look at what these metrics mean, see our guide to Core Web Vitals explained. For a deeper dive into the full range of performance improvements available, see our page speed optimisation guide.

6. Capture your internal linking structure Internal links pass authority around your site. If your new structure changes where links point, you could inadvertently orphan important pages. Screaming Frog can export your full internal link map.

How Do You Build a Redirect Map?

A redirect map is a spreadsheet that matches every old URL to its new equivalent. It is the single most important document in any website migration.

The format is simple:

Rules for a good redirect map:

• Every old URL that no longer exists must have a 301 redirect to the most relevant new page
• If a page's content is being removed entirely with no equivalent, redirect to the nearest parent (e.g., a deleted blog post redirecting to /blog/)
• Avoid redirect chains — if old page A redirects to old page B which redirects to new page C, you've added delay for every visitor. Google advises redirecting to the final destination directly
• 302 redirects signal a temporary move — use 301 for permanent URL changes

Google's site move guidance says permanent redirects such as 301 are the right choice, and that "301 and other permanent redirects don't cause a loss in PageRank". It also says that a small to medium-sized site can take a few weeks for most pages to move, and larger sites take longer.

Worked Example: A Small Redirect Map

Here is a short example for a fictional plumber. The paths are made up, so replace them with your own.

How to spot-check redirects after launch

• In a terminal, run curl -I followed by an old URL. You should see a 301 status and a Location line showing the new address.
• Run curl -IL to follow the hops. A good redirect reaches the new page in one step and ends on a 200.
• For a long list, upload your old URLs into a crawler such as Screaming Frog and check the status codes and final destinations.
• Open a handful of old URLs in a browser too, including your top pages from Search Console.

Should You Run the New Site in Staging First?

Absolutely. A staging environment is a version of your new site hosted at a private URL (e.g., staging.yourdomain.co.uk) that is blocked from search engines via robots.txt or basic authentication.

On staging, you should:

• Crawl the new site with Screaming Frog and check for broken links, missing pages, and incorrect canonical tags
• Validate all redirect rules are in place by testing the old URLs against expected destinations
• Check the XML sitemap only contains the pages you want indexed
• Confirm noindex tags are not accidentally applied to live pages
• Test meta titles, descriptions, and H1s across all key pages
• Verify structured data using Google's Rich Results Test

Time spent on staging QA can save a lot of recovery work later. Every custom website project we build at Brambla includes a staging site for testing before launch, and we set up Search Console for the new site.

During Migration: Launch Day Checklist

What Should Happen on Go-Live Day?

The launch itself should be executed systematically. Work through this checklist:

What Are the Most Common Migration Mistakes?

1. Forgetting pages that aren't in the main navigation Blog posts, old landing pages, resource PDFs, and product pages buried in categories are easy to miss. Screaming Frog will catch them if you crawl the live site before migration — but only if you run the crawl from your sitemap as well as your homepage.

2. Launching with the staging robots.txt This is one of the most damaging errors in web development. If a developer forgets to update robots.txt from Disallow: / (which blocks all crawlers on staging), Google is told not to crawl the new site. That stops it from picking up your new pages and redirects, so fix it as soon as you spot it.

3. Changing URL structure without redirects If your old site used /services/web-design-and-build/ and the new site uses /services/web-design/, that's a new URL in Google's eyes. Without a redirect, the old URL still exists in Google's index pointing to a 404. Your rankings for the old page are lost.

4. Reducing content significantly A page that ranked well had content Google valued. If the new design strips that page down from 1,200 words to 200 words, you've removed the signals that supported the ranking. Migrations are often wrongly blamed for traffic loss that is actually a content thinning problem.

5. Not accounting for international or multilingual content If your site had hreflang tags for multiple countries or languages, Google says to update them to use the new URLs. Leaving them pointing at old URLs is an easy mistake to make in international migrations.

Post-Migration: Monitoring and Recovery

How Long Does It Take to Recover Rankings After a Migration?

This is the question every client asks, and the honest answer is: it depends, and nobody can promise zero traffic loss.

Google's site move guidance says that "a small to medium-sized website can take a few weeks for most pages to move, and larger sites take longer". It also says visibility "may fluctuate temporarily during the move. This is normal and a site's rankings will settle down over time."

Two things we'd plan around:

• Redirects stay live for a long time. Google says to keep them "for as long as possible, generally at least 1 year", so it can transfer all signals to the new URLs.
• Gaps slow everything down. Missing redirects, cut content and crawl errors are what turn a short dip into a long one. We can't give you a fixed recovery date for any site, and we don't promise one.

What Should You Monitor Post-Migration?

Set up a post-migration monitoring cadence:

After launch, our WebsiteCare plans cover hosting, security and uptime monitoring, and the Growth and Premium plans add performance audits. Content migrations between CMS platforms are quoted separately.

What If Rankings Drop After Migration?

A temporary dip is normal. A sustained drop is a signal to investigate. Work through this diagnostic sequence:

Step 1: Identify which pages dropped Use Search Console Performance, filtered by page, sorted by change in clicks. This tells you exactly which pages have been affected.

Step 2: Check for redirect gaps Take the dropping page URLs and run them through your old URL list. If any are missing from your redirect map, fix them immediately.

Step 3: Compare content Open the old page from your pre-migration crawl export (or a saved copy) and compare it against the new page. Has content been cut? Have headings changed significantly? Have internal links been removed?

Step 4: Check indexation Use site:yourdomain.co.uk/page-slug/ in Google to confirm the page is indexed. Check Search Console's URL Inspection tool for crawl date and index status.

Step 5: Check Core Web Vitals A page that was previously fast but is now slow may lose ranking positions. Run the new page through PageSpeed Insights and compare against the pre-migration benchmark.

If the drop is widespread rather than page-specific, the issue is more likely technical — a robots.txt problem, a sitemap issue, or a sitewide canonicalisation error. If rankings don't recover after fixing technical issues, our Google core update recovery guide covers how to diagnose and address deeper ranking loss.

Tools for Website Migration SEO

You don't need all of these — Search Console and Screaming Frog cover most scenarios for small business migrations.

Is a Website Redesign Always an SEO Risk?

No — done correctly, a redesign is an SEO opportunity. A new site that is faster, better structured, more authoritative, and more aligned with user intent will outperform the old one. The risk comes from poor execution, not from migration itself.

If you're planning a redesign and worried about losing rankings, the answer is not to delay — it's to plan the migration properly. See our full website redesign checklist for a broader perspective on what a successful redesign involves.

For businesses with significant organic traffic, commissioning a website audit before migration gives you a clear picture of what's worth protecting and where the risks lie.

Frequently Asked Questions

How long does website migration SEO take to stabilise?

Google says a small to medium-sized site can take a few weeks for most pages to move, and that rankings settle down over time. Larger sites take longer. We can't give you a fixed date, and gaps such as missing redirects or cut content make recovery slower.

Do 301 redirects pass full link equity?

Google's site move guidance says "301 and other permanent redirects don't cause a loss in PageRank". The key is that the redirects point to the right pages and stay in place. Google says to keep them for as long as possible, generally at least a year.

Should I tell Google about my migration?

Yes. Submit your new XML sitemap to Google Search Console immediately after launch. If you're moving from one domain or subdomain to another, use the Change of Address tool in Search Console once your redirects are live. Google says you don't need it for HTTP to HTTPS moves, www to non-www switches, or moving pages within the same domain.

Can I migrate and redesign at the same time?

You can, but it increases risk. The more changes you make simultaneously, the harder it is to diagnose problems if rankings drop. If your budget and timeline allow, consider a phased approach: migrate first (same design, new platform), stabilise, then redesign.

What is a redirect chain and why does it matter?

A redirect chain is when URL A redirects to URL B, which redirects to URL C. Each hop adds delay for visitors. Google says Googlebot can follow up to 10 hops, but advises redirecting to the final destination directly.

Does changing my CMS (e.g., WordPress to Webflow) hurt SEO?

Changing CMS is only an SEO issue if it changes your URLs, removes content, or changes how Google crawls your site. With proper redirect mapping and content parity, a CMS change should be SEO-neutral or positive (if the new platform is faster or better structured).

Related Reading

• The Complete Guide to Website Redesign
• Core Web Vitals Explained: What They Are and Why They Matter
• SEO for Small Businesses: A Practical Guide
• How Much Does a Website Cost in the UK?
• Page Speed Optimisation: The Complete Guide

Ready to Migrate Without the Anxiety?

A website migration doesn't have to be a gamble with your rankings. With the right planning, the right tools, and a development partner who treats SEO as part of the build — not an afterthought — you can upgrade your site without losing the visibility you've worked hard to build.

At Brambla, when we rebuild an existing website, we map your old URLs to the new ones with 301 redirects as part of the launch. If you're not sure where your current site stands, start with a website audit — we'll show you exactly what needs protecting before you touch anything. Or if you'd like to talk through your migration, get in touch, or view our pricing to find the right package.