Should you submit a temporary sitemap with old and new URLs during a migration?

Why does Google recommend including old URLs in a temporary sitemap?

During a migration, Google needs to discover the redirects to transfer ranking signals from old pages to new ones. A standard sitemap only lists the final URLs accessible via a 200 status. But by adding the old URLs (those that redirect with 301), you prioritize crawling efforts for Googlebot.

The recent date in the sitemap acts as an urgency signal. Google interprets dated entries as modified or new content deserving of quick attention. By combining old and new URLs in a single file, you create a complete before/after map that helps Google understand the migration structure without guesswork.

How does this temporary sitemap impact the crawl budget?

The crawl budget is not infinite. During a poorly prepared migration, Googlebot can waste time crawling pages it only discovers through random internal links. A temporary sitemap centralizes critical URLs and gives them explicit priority in the crawl queue.

This approach is especially effective for large sites (thousands of pages). Instead of waiting for Google to discover each redirect organically, you accelerate the discovery process and reduce the period during which old URLs continue to appear in the index.

What is the difference from a standard permanent sitemap?

A permanent sitemap should only contain URLs that are accessible with a 200 status. Adding 301 URLs is officially discouraged in Google’s standard documentation. The temporary sitemap discussed by Mueller is an exception: it is a tactical tool for a specific phase, that of migration.

Once Google has processed the migration (usually within weeks), this sitemap should be removed or replaced with a standard sitemap. Keeping a sitemap filled with redirects is counterproductive in the long term: Google will eventually consider it poorly maintained and may ignore its signals.

• Temporary Sitemap: includes old + new URLs, recent dates, removed after migration
• Speeding Up Crawl: Google prioritizes listed URLs instead of discovering them randomly
• Freshness Signal: recent dates prompt Googlebot to recrawl quickly
• Limited Duration: do not keep this sitemap in production after migration validation
• Applicable mainly to large sites: on a 50-page site, the impact is negligible

Is this recommendation consistent with field observations?

Yes, but with significant nuances. Migrations tracked with a temporary sitemap do indeed show a faster recrawl of critical URLs. However, the actual impact depends on the site size, existing crawl budget, and quality of the redirects.

On a 500-page site with good authority, the difference between a temporary sitemap and a standard migration is often minimal. On the other hand, on a 50,000-page site with a tight crawl budget, this tactic can reduce the complete processing time of redirects by several weeks. [To be verified]: Google does not provide precise numbers on real-time savings.

What are the practical limits of this method?

The first pitfall: thinking that a temporary sitemap compensates for a poorly prepared migration. If your redirects are misconfigured (chains, loops, 302 instead of 301), the sitemap won’t solve anything. Google will crawl faster, but it will also encounter errors more quickly.

The second limitation: generating the file. Creating a sitemap with old + new URLs requires a clean and comprehensive mapping. In a complex migration (redesign + structure change + domain merger), this file can become a nightmare to maintain. And if you forget it in production after migration, you send conflicting signals to Google for months.

In what cases is this tactic essential?

It becomes critical in three types of projects: large e-commerce site migrations (where each day of lost ranking is costly), redesigns involving radical URL structure changes, and multi-domain migrations (merging acquisitions). In these contexts, every optimization that reduces recrawl latency has a measurable ROI.

However, on a blog with 200 articles or a showcase site with 30 pages, the effort to create and maintain the temporary sitemap often exceeds the benefit. Google will handle the migration within a few days anyway. Focus your resources on the quality of redirects and the consistency of the internal linking; that will have a greater impact.

How do you concretely create this temporary sitemap?

Start by exporting the complete list of your old URLs from your previous CMS or via a Screaming Frog crawl. Map each old URL to its new destination (Excel file or CSV). Then use a XML sitemap generator (python, WP plugin, custom script) to create a file with both URL columns as <loc> entries.

For the date, use the production date of the migration for all entries. Submit this sitemap via Google Search Console in a dedicated section, separate from your permanent sitemap. Name it explicitly (e.g., sitemap-migration-temp.xml) so you don’t forget it later.

What mistakes should you absolutely avoid?

Number one mistake: leaving the temporary sitemap online after migration. Remove it as soon as Google has recrawled 90%+ of the URLs (check in Search Console, Coverage section). If you leave it, Google will continue to crawl unnecessary redirects, polluting your stats and diluting your crawl budget.

The second common mistake: including URLs blocked by robots.txt or orphan pages without internal links. Google will crawl these URLs because they're in the sitemap, discover they are inconsistent with the rest of the site, and you will lose overall credibility. Clean your mapping before generating the file.

How do you verify that the tactic is working?

In Search Console, monitor two metrics: the number of URLs crawled per day (should increase just after submitting the sitemap) and the status of old URLs in the index (should gradually change from "Indexed" to "Redirected"). If after 7-10 days you see no changes, check that Google has properly detected the sitemap.

Also use a tool like Oncrawl or Botify to track actual visits by Googlebot to old URLs. If the bot isn't crawling them despite the sitemap, it's often a global crawl budget issue or a quality of redirects concern. These technical optimizations require sharp expertise: if you're not comfortable with server logs and redirect debugging, guidance from a specialized SEO agency can secure the migration and prevent costly traffic losses.

• Map all old URLs to their new destinations in a clean file
• Generate an XML sitemap including old + new URLs with migration date
• Submit the temporary sitemap via Search Console in a dedicated section
• Monitor the recrawl in Search Console (Coverage section + Crawl Stats)
• Remove the temporary sitemap once 90%+ of redirects are processed
• Check server logs to confirm Googlebot’s visits to old URLs