Google merges hreflang signals from HTML and sitemaps

If hreflang attributes are contained in both HTML and Sitemap, then Google will combine and use all of these signals. This was revealed by search employee John Mueller during a recent Google Search Central hangout.

The question to Mueller was about handling conflicting hreflang directives. For example, if the correct hreflang attributes are embedded using sitemaps, and the web pages also contain these attributes, but not the most correct ones.

“Does Google prioritize hreflang attributes for sitemaps or on-page, or vice versa?” The author asked.
Mueller first clarified what exactly is meant by "conflicting" signals.

The technician explained that the attributes conflict in the sense that the correct directive is contained in the sitemap file (English for US users), while the source code of the same page contains an indication of French for the US.

According to Mueller, if hreflang attributes are added to both the sitemap and the page source, then Google will merge those signals.

From a search engine perspective, a page can be targeted to multiple countries / regions. For example, this page may appear to English speaking users in Singapore, the US and the UK, but a different page will be targeted to English speaking users in Australia.

Therefore, Google will combine these signals.

An exception is possible only if these signals are not synchronized with each other. For example, if a specific regional version is specified in the hreflang on a page, and the same directive is assigned to another page in the Sitemap. In this case, Google systems will try to guess which directive to use, or they will miss these signals.

When it comes to prioritization, Google doesn't prioritize HTML or Sitemap.

You can listen to the answer to the question to Mueller and his answer to it in the video below: