Website migrations — whether changing domains, CMS platforms, URL structures, or HTTP to HTTPS — are among the highest-risk SEO activities a site owner undertakes. A well-executed migration preserves your rankings through the transition and recovers any temporary dips within weeks. A poorly executed one can lose years of accumulated SEO authority and take months to recover. The difference between the two is almost entirely in the preparation.
Types of Site Migrations
Domain migration — moving from one domain to another. The highest risk migration type because every URL changes and all external backlinks point to the old domain. Requires comprehensive 301 redirects and an explicit domain change notification to Google.
HTTP to HTTPS migration — as we covered in our guide to HTTPS and SEO, this is now essential for all sites. It is also one of the most commonly botched migrations — failing to redirect HTTP to HTTPS correctly, leaving mixed content, or missing canonical tag updates.
URL structure changes — restructuring your site's URL patterns, often as part of a CMS migration or site redesign. Every changed URL requires a 301 redirect as covered in our guide to 301 redirects.
CMS migration — moving from one platform to another (WordPress to a custom CMS, for example). Often combined with URL structure changes, making it the most complex migration type.
Pre-Migration Checklist
☐ Crawl your current site completely. Use our site scanner to document every URL, title tag, meta description, H1, and internal link on your current site. This is your baseline and your redirect mapping source.
☐ Download your Search Console data. Export your top performing queries and pages. This documents your pre-migration rankings for post-migration comparison.
☐ Export your backlink data. Document which URLs have external backlinks pointing to them — these are the URLs that most need working 301 redirects to preserve link equity.
☐ Map every old URL to its new equivalent. Create a complete redirect map before touching anything. Every current URL should map to a specific new URL. Where a one-to-one equivalent does not exist, map to the most relevant category or parent page.
☐ Test on staging first. Implement all redirects, canonical tags, and technical changes on a staging environment and verify everything works before touching the live site.
Migration Execution
Implement all 301 redirects before removing any old URLs. As we covered in our guide to redirect chains, implement direct redirects from old URLs to final destinations — avoid chains. Update all internal links to point to new URLs directly rather than relying on redirects. Update your sitemap to reflect only new URLs.
Post-Migration Monitoring
The first four weeks after migration are critical. Check Google Search Console daily for crawl errors — 404s appearing after migration indicate redirects that were missed. Monitor your ranking positions for top keywords. Some temporary ranking fluctuation is normal — a 10–20% traffic dip for two to four weeks is common and expected. A continuing decline beyond four weeks indicates a structural problem requiring investigation.
Run our broken link checker on the new site immediately after launch and weekly for the first month. Update your sitemap and submit it to Search Console. Request indexing for your highest-priority pages through the URL Inspection tool as covered in our guide to getting pages indexed faster.
Summary
Successful site migration requires comprehensive pre-migration crawling and documentation, complete 301 redirect mapping, staging environment testing, and intensive post-migration monitoring. Prepare more thoroughly than you think necessary — every missed redirect is a ranking loss that takes weeks to recover. Use our site scanner before and after migration to catch technical issues at every stage.
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