Hreflang errors: how to find and fix them

What it means

An hreflang annotation points from page A to page B, but page B does not point back to page A. This breaks the bidirectional requirement — every version must list itself and all its siblings.

Why it matters

Without return links, Google cannot reliably pair language variants, which can cause it to index the wrong version, drop cross-references, or treat pages as separate entities. That hurts crawl efficiency and can prevent AI agents from resolving the correct regional or language version.

How to fix it

1. Add a self-referencing hreflang tag on every page version (it must list itself).
2. Add reciprocal <link rel="alternate" hreflang="xx" href="absolute-url-of-the-other-version" /> on the target page pointing back.
3. Use fully-qualified absolute URLs in all hreflang entries — no relative paths.
4. Validate the markup with a crawler or the hreflang validator to confirm bidirectional coverage.

Example

<!-- /en/ links to /fr/ ... -->
<link rel="alternate" hreflang="fr" href="https://example.com/fr/">
<!-- but /fr/ has NO link back to /en/ -->

<!-- /en/ -->
<link rel="alternate" hreflang="fr" href="https://example.com/fr/">
<!-- /fr/ must include the return link -->
<link rel="alternate" hreflang="en" href="https://example.com/en/">

hreflang must be reciprocal: if A points to B, B must point back to A, or Google drops the pairing.

When it's not a problem

If the site uses a single language without regional variants, or if hreflang is applied only to a subset of pages that don't need pairing, the warning is harmless. Also fine when hreflang is set via HTTP headers on PDFs or non-HTML resources where return links aren't applicable.

How Crawlinx detects it

After the crawl builds the page graph, we follow each hreflang target and check it links back to the source. A target that omits the return link is reported as non-reciprocal.

How common is it?

552 audited sites in our corpus currently show this issue. The breakdowns below show which platforms, gatekeepers, verticals and countries are most exposed.

FAQ

What is a missing hreflang return link?

When page A declares B as its alternate but B doesn't declare A in return. Google treats hreflang as bidirectional and ignores one-way pairings.

Related guides

• Hreflang and International SEO: A Practical Guide