How to Manage Canonical Tags During a Site Migration
Canonicals and hreflang must agree with your redirects, or they send mixed signals. Here is what canonical tags do, how to update them for the new URLs, and how to handle hreflang during an international migration.
Canonical tags tell search engines which version of a URL is the preferred one, so during a migration they must be updated to point to the new URLs, or they keep referencing old addresses and confuse indexing. A canonical must never contradict your redirects: both should point to the new URL. Hreflang tags tell search engines which language or regional version to show, and because they reference specific URLs, they too must be updated on an international migration. Handle hreflang by updating every reference, keeping return references consistent, and testing after launch. Everything should agree with your redirects.
What canonicals do, and why they must be updated
Canonical tags tell search engines which version of a URL is the preferred one, so during a migration they must be updated to point to the new URLs, otherwise they can still reference the old addresses and confuse indexing. A canonical left pointing at an old URL sends a mixed signal; because canonicals influence which URL search engines index, updating them to the new addresses is an essential migration task. Canonicals must be updated for the new URLs because a canonical still pointing to an old URL tells search engines the old address is preferred, which conflicts with your redirects and can slow or confuse the move to the new site. The canonical and the redirect should agree, both pointing to the new URL, reinforcing the 301 redirects rather than fighting them; because contradictory signals undermine a migration, canonicals must be updated so they reinforce rather than fight the new structure.
Point to new URLs
Update every canonical.
Agree with redirects
One consistent signal.
Hreflang too
Update on international moves.
Hreflang tags, handling them internationally, and aligning with redirects
Hreflang tags tell search engines which language or regional version of a page to show to which users, and they matter during an international migration because, like canonicals, they reference specific URLs that change when the site moves. If hreflang tags keep pointing at old URLs, the wrong or missing versions can be served; because they depend on URLs, hreflang tags on multilingual sites must be updated to the new addresses as part of the migration. You handle hreflang during an international migration by updating every hreflang reference to point to the new URLs, keeping the return references consistent so each language version correctly points to the others, and testing them after launch to confirm the right versions are being served. Consistency across all language versions is essential for hreflang to work; because errors are easy to introduce, careful updating and testing of hreflang is important on any international migration. Canonicals and hreflang fit with redirects by all agreeing with them, every one pointing to the correct new URL, so that search engines receive a single, consistent message about the new structure. When redirects, canonicals and hreflang align, the migration signals are clean. Because mixed signals cause confusion and delay, aligning these tags with your redirects is what keeps indexing on track, alongside careful handling of structured data.
One consistent signal.
No contradictions.
Canonicals and hreflang that still point at old URLs quietly fight your redirects and confuse indexing. We update every canonical and hreflang reference to the new URLs, keep multilingual return references consistent, and test them after launch, so every signal agrees and the move stays clean.
Everything included in your plan:
One clear retainer. No setup fee.