Site Migration That Does Not Cost You Your SEO
WordPress, Next.js, Drupal, Shopify, custom platforms. From 1,000 pages to 100,000+. The technical move is the easy part — preserving ranking equity is what separates a clean migration from a disaster.
BOOK YOUR 30-MIN CALLWHAT GOES WRONG IN MOST SITE MIGRATIONS
I have watched five-figure migrations turn into six-figure SEO disasters because the team treated migration as a technical problem instead of a continuity problem. The pattern is always the same: build the new site, throw a switch, watch organic traffic drop 40-70% over the next eight weeks, then spend the next quarter trying to recover.
The technical move is rarely what kills you. Redirect maps that are 80% complete kill you. Canonical tags pointing at staging domains kill you. Internal links that still point at the old structure kill you. URL changes done "while we are at it" kill you.
HOW WE DO MIGRATIONS DIFFERENTLY
Five non-negotiables, learned the hard way over 12,000+ sites at Seahawk Media:
- Complete redirect map before any code is written. Every old URL gets a 301 to its new counterpart. We export the source URL list, then build the mapping in a spreadsheet that becomes the source of truth for the cutover.
- URL structure preservation. Every URL change is a ranking risk. We change URLs only when there is a content reason to — never because the new platform suggests a different convention.
- Phased rollout for 10K+ page sites. Migrate the lowest-traffic content first, validate that rankings hold, then expand. A staged migration limits blast radius if something goes wrong.
- Parallel-run period. The old site stays live in read-only mode for 30 days post-launch. If the new site has an issue, traffic gets re-routed back instantly.
- 90 days of post-launch monitoring. Search Console crawl stats, indexation coverage, impressions, log file analysis. Fix regressions in days, not quarters.
WHO THIS SERVICE IS FOR
- WordPress to Next.js or Astro — keeping content authors happy while picking up modern performance and headless flexibility
- Drupal, Sitecore, or Typo3 to WordPress — moving off legacy enterprise CMS without breaking the SEO rankings the legacy team built up
- Shopify to headless commerce — Shopify Plus storefront with a Next.js or Hydrogen front-end, full custom design, faster Core Web Vitals
- Domain consolidation — multiple legacy domains merging into one, with proper canonical and redirect strategy across all of them
- Subdomain to subdirectory consolidation — moving blog.example.com to example.com/blog/ to consolidate link equity
- Hosting and platform migrations — moving managed WordPress between Kinsta, WP Engine, Pressable, or to bare-metal infrastructure
HOW LONG IT TAKES
- Under 1,000 pages — 4-8 weeks end-to-end
- 1,000 to 10,000 pages — 12-20 weeks
- 10,000 to 100,000+ pages — 6-9 months minimum, phased rollout, parallel-run period
The biggest variable is content quality at source. Messy taxonomies, duplicate URLs, and inconsistent metadata add weeks to the planning phase. We will tell you honestly during the audit whether your source site is migration-ready or whether it needs a content cleanup first.
WHAT IT COSTS IN 2026
- Small business under 500 pages: £4,000-£12,000
- Mid-market 1,000-10,000 pages: £15,000-£60,000
- Enterprise 10,000-100,000+ pages: £60,000-£300,000 including ongoing post-launch SEO support
About 30-40% of the cost goes to planning and QA, not the technical build. The teams that quote you cheap are the ones who skip the planning — and you pay for it later in lost rankings.
FREQUENTLY ASKED QUESTIONS
What is site migration?
Site migration is moving a website from one platform, host, domain, or technical architecture to another while preserving SEO rankings, content integrity, and user experience. Common migrations include WordPress to Next.js, Shopify to headless commerce, or moving from one CMS like Drupal or Sitecore to WordPress. The technical move is the easy part — preserving SEO equity is what separates a clean migration from a disaster.
How long does a site migration take?
For sites under 1,000 pages: 4-8 weeks end-to-end including planning, redirect mapping, content migration, QA, and post-launch monitoring. For 10,000-20,000 page sites: 12-20 weeks. For enterprise migrations of 50,000+ pages: 6-9 months minimum, with phased rollouts and parallel-run periods. The biggest variable is content quality at source — messy taxonomies and duplicate URLs add weeks.
How do I migrate a site without losing SEO rankings?
Three non-negotiables. First, build a complete redirect map: every old URL gets a 301 to its new counterpart, no exceptions. Second, preserve URL structure where possible — every URL change is a ranking risk. Third, monitor Search Console crawl stats, indexation, and impressions for 90 days post-launch and fix regressions immediately. Add log file analysis to catch crawl waste before it costs you.
What is the cost of a site migration in 2026?
For a small business site under 500 pages: £4,000-£12,000. Mid-market 1,000-10,000 pages: £15,000-£60,000. Enterprise 10,000-100,000+ pages: £60,000-£300,000 with ongoing post-launch SEO support. Expect 30-40% of total cost on planning and QA, not the technical build itself. The teams that quote you cheap are the ones who skip the planning.
What is the difference between a redirect and a canonical?
A 301 redirect is the server telling the browser "this URL has permanently moved" — Google honours it and transfers nearly all ranking signal to the new URL. A canonical tag is a hint to Google saying "if you find this page through multiple URLs, treat THIS one as the source of truth". Use redirects when content has actually moved. Use canonicals to consolidate duplicates without removing alternatives. Confusing them is the #1 self-inflicted SEO injury during migrations.
Should I migrate to WordPress, Next.js, or stay where I am?
It depends on what is actually broken. If your problem is content authoring friction, a CMS migration helps. If your problem is performance, a stack migration to Next.js or Astro might. If your problem is SEO and your current site ranks well, the safest move is often to stay and fix the specific issues. I have shipped 12,000+ sites through Seahawk Media — happy to give you an honest second opinion before you commit.
Who should run the migration — agency, in-house, or both?
For migrations under 1,000 pages, a competent in-house developer with an SEO advisor on call is enough. For migrations over 5,000 pages, you need an agency that has done it before — the patterns and pitfalls are too numerous to learn in real-time. For 50,000+ pages, you need a dedicated migration team with phased rollout, parallel-run, and a war-room cadence for the cutover week.
What is a redirect map and why does it matter?
A redirect map is a one-to-one mapping of every old URL on the source site to its destination URL on the new site. For a 10,000-page migration, that is a 10,000-row spreadsheet that gets converted into 301 redirect rules in your hosting config. Without it, traffic to discontinued URLs hits a 404 and Google strips ranking signal from those pages over weeks. With it, ranking equity transfers cleanly.
WHEN YOU ARE READY TO TALK
Migrations live or die in the planning phase. The fastest way to know whether yours will go cleanly is a 30-minute audit call.
BOOK YOUR 30-MIN CALL