Is it really necessary to combine both 301 redirections AND canonical tags for an HTTPS migration?

Why does Google impose this technical dual requirement?

Google's official stance on this subject is clear: during an HTTP to HTTPS migration, the publisher must implement permanent 301 redirections AND canonical tags on HTTPS pages pointing to themselves. This approach may seem redundant at first glance.

The rationale behind this recommendation is based on the desire to maximize canonicalization signals. A 301 redirection already indicates the new address, but Google treats canonical tags as an additional signal that speeds up consolidation. During the transition period, some crawlers may still access old HTTP URLs via outdated backlinks or alternative paths.

Does this statement change established practices?

Not really. Most modern CMSs automatically generate self-referencing canonical tags on every page. What Google is formalizing here is mostly an explicit validation of an already widespread practice.

The new aspect relates more to the tone used: Google emphasizes the term 'essential', suggesting that a migrated site without a canonical tag risks experiencing delays in signal consolidation (PageRank, links, history). In practical terms, this could mean a few extra weeks before the old HTTP version completely disappears from the index.

What are the risks of not having a canonical tag on HTTPS?

Without a canonical tag on the HTTPS pages, Google must rely solely on the 301 redirection to understand the architecture. If there are alternative paths leading to the HTTP version (for example, a broken internal link or an outdated XML sitemap), the engine might temporarily index both versions.

This scenario creates a dilution of ranking signals: backlinks pointing to HTTP take longer to transfer to HTTPS, and the old URL may remain visible in the SERPs for several weeks. The canonical acts as an additional lock that speeds up the switch.

• 301 Redirections: strong signal of canonicalization, but requires that all HTTP URLs are effectively redirected
• Canonical Tags: reinforce the declaration of the canonical version, even if alternative paths exist
• Combination of both: a defensive approach that limits interpretation errors by the engine during migration
• Risk of inconsistency: if canonical and redirection point to different URLs, Google generally favors the redirection

Is this statement consistent with field observations?

On paper, this recommendation seems logical. In practice, the majority of successful HTTPS migrations rely almost exclusively on 301 redirections. Self-referencing canonicals are present by default, but their absence has never blocked a migration across the dozens of sites I have worked on.

What is problematic is the term 'essential' used by Google. Let's be honest: a well-configured 301 redirection is sufficient in 95% of cases. The canonical adds a layer of security, but labeling its absence as critical reflects a overestimation of the actual risk. [To verify] whether this recommendation arises from specific incidents observed by Google or is simply a general precaution.

What nuances should be added to this rule?

The first nuance: the presence of a canonical tag only accelerates migration if all other conditions are met (consistent 301 redirections, updated XML sitemap, corrected internal links). Adding a canonical without correcting the HTTP paths in the internal linking does not resolve anything.

The second nuance: some CMSs generate canonicals with parameters or URL variations (trailing slash, www vs non-www). In this case, a poorly configured canonical can create more problems than it solves. Better to have no canonical at all than an incoherent one with the 301 redirection.

When does this rule become truly critical?

The canonical makes sense on sites with a complex architecture: millions of pages, multiple URL parameters, subdomains, language versions. In these contexts, the 301 redirection does not always cover all possible paths to the same resource.

Another concrete case: sites that temporarily maintain HTTP access in certain sections (for example, a blog not immediately migrated). Here, the canonical helps to clarify which version should be indexed even if both remain accessible. It’s a safety net that limits interpretation errors during the transition phase.

What should you concretely do during an HTTPS migration?

The priority remains the implementation of permanent 301 redirections for all HTTP URLs to their HTTPS counterparts. This is typically configured at the server level (Apache, Nginx) or via a plugin if you are using a CMS. Test each redirection individually on a representative sample before deploying across the entire site.

Next, check that your HTTPS pages contain a self-referencing canonical tag pointing to themselves. Most modern CMSs (WordPress, PrestaShop, Magento) manage this automatically. If not, add a <link rel="canonical" href="https://yoursite.com/page"> tag in the <head> of each template. Ensure that the URL in the canonical exactly follows the final HTTPS structure.

What mistakes should be absolutely avoided?

The classic mistake is to redirect in 301 to HTTPS while leaving an HTTP canonical in the source code of the HTTPS page. This creates an inconsistency: Google receives a signal to redirect to HTTPS, but the canonical tells it that the HTTP version remains canonical. Result: chaotic indexing and loss of rankings for several weeks.

Another frequent trap: forgetting to update the XML sitemap. If your sitemap continues to list HTTP URLs after migration, Google will crawl those URLs, detect the redirections, but will consider the site as misconfigured. The sitemap must exclusively contain the final HTTPS URLs from day one of migration.

How can you verify that the configuration is correct?

Use a crawler like Screaming Frog or OnCrawl to audit the entire site. Check that each HTTP URL returns a 301 code (not 302, no redirect chains). Then verify that each HTTPS page contains a consistent self-referencing canonical. If you detect canonicals pointing to HTTP, correct them immediately.

In Google Search Console, monitor the index coverage report. HTTP URLs should gradually disappear in favor of HTTPS. If you observe HTTP URLs remaining indexed for several weeks after migration, it’s likely a problem of conflicting signals between redirection and canonical. Support from a specialized SEO agency can be invaluable to diagnose and quickly correct these inconsistencies, especially in complex architectures where each day of confusion in the index represents lost visibility.

• Set up permanent 301 redirections for all HTTP URLs to HTTPS
• Verify that each HTTPS page contains a self-referencing canonical tag pointing to HTTPS
• Update the XML sitemap to exclusively include HTTPS URLs
• Correct all internal links to point directly to HTTPS
• Audit the site with a crawler to detect canonical/redirection inconsistencies
• Monitor Google Search Console to confirm the gradual switch in indexing