Site migration without avoidable loss
TL;DR
- Any migration with URL changes risks traffic loss if done poorly.
- The heart of it is a complete 301 redirect map, one to one.
- Validate before and after, and monitor in Search Console.
- Plan ahead; don't migrate in a rush.
Changing domain, CMS or restructuring URLs can cost you hard-won organic traffic - or not, if executed well. The difference is method.
The steps you can't skip
| Step | Action |
|---|---|
| URL map | Complete inventory, old to new, one to one |
| 301 redirects | Permanent, no chains or loops |
| Validation | Test redirects and schema before publishing |
| Monitoring | Coverage and positions in Search Console post-migration |
It's a demanding technical project; if you're planning a migration, get in touch and see the technical SEO checklist.
The redirect map is the whole game
Almost every "we lost traffic after the migration" story traces back to one thing: an incomplete or lazy redirect map. Every old URL that had value - traffic, backlinks, rankings - must point, with a single 301, to its closest equivalent on the new site. Not a blanket redirect to the homepage (Google treats that as a soft 404), not a chain of three hops, not a 302. Crawl the old site first so you have the complete inventory, prioritize the URLs with real backlinks and organic traffic, and map those by hand.
Types of migration - and where each bites
They're not equally risky. A domain change is mostly redirects plus a Search Console change-of-address. A URL restructure lives or dies on the mapping. A CMS/platform change (or a redesign) is the dangerous one, because URLs, templates, internal links and rendering all move at once - so problems hide behind each other. Whichever it is, change one variable at a time where you can; migrating platform and redesigning content in the same release makes any traffic drop nearly impossible to diagnose.
A migration timeline
- Before: crawl the old site, build the one-to-one URL map, prepare redirects, and benchmark rankings and traffic.
- Staging: test redirects, canonicals and schema on a non-indexable staging site.
- Launch: deploy redirects with the switch, submit the new sitemap, and (for a domain move) file the change of address in Search Console.
- After: watch coverage, redirects and positions daily for the first weeks; fix any 404s and redirect chains fast.
A temporary dip in the first days is normal as Google reprocesses; a sustained drop means something in the map is wrong. Plan ahead - the rushed migration is the one that costs months.
Key data
| Clean 1:1 301s (done right) | >95% retained |
|---|---|
| Botched migration | ~50% loss |
| PageRank lost via 301 | 0% |
| Typical recovery | 2 wks–3 mo. |
Loss/recovery percentages come from agency cases and vary widely.
Sources: Google Search Central — site moves
Common mistakes and how to do it right
I've seen businesses lose months of traffic in a rushed migration. Learn from others' pain:
| Avoid | Do |
|---|---|
| ✗ Migrating without a complete URL map | ✓ A one-to-one inventory, old to new |
| ✗ Using 302 (temporary) for permanent changes | ✓ 301 permanent, to transfer signals |
| ✗ Chaining redirects (A to B to C) | ✓ A direct A to C redirect, no chains |
| ✗ Publishing and praying | ✓ Validating before and monitoring Search Console after |
Tools I use and recommend
- Screaming Frog SEO SpiderDesktop crawler for deep technical and on-page audits.
- Google Search ConsoleOrganic performance, coverage and field Core Web Vitals.
- SemrushKeywords, site audit and competitor analysis.
Sources
Frequently asked questions
Which redirect for a migration?
301 (permanent), to pass signals to the new URL. Avoid chains and temporary redirects. Technical checklist →
Will I definitely lose traffic?
No, if the redirect map is complete and execution careful. Loss almost always comes from avoidable errors. See service →