Invalid hreflang language code: how to fix it

Invalid hreflang codes break international targeting. Find hreflang tags with errors in their language or region codes and learn the correct format.

audited sites affected

What it means

Google has parsed an hreflang tag on your page but cannot recognize the language code inside it. The code is either malformed (a region-only value like GB instead of en-GB), non-standard (like es-419 or EU or UK), or missing required hyphenation.

Why it matters

Invalid hreflang codes break the bidirectional return-tag relationship: if one version points to another with a bad code, the partner page won't point back, so Google may treat each version as a separate page rather than as language variants. This dilutes ranking signals across regions and can cause the wrong language version to appear in regional SERPs or AI Overviews.

How to fix it

Replace every region-only code with a language prefix (e.g., GB → en-GB, UK → en-GB).
Verify all hreflang values are standard ISO 639-1 language codes, optionally followed by a hyphen and ISO 3166-1 Alpha-2 region code (e.g., de, en-GB, zh-Hant).
Confirm every version lists itself plus all others, and that all URLs are absolute and fully qualified.
Validate the markup with a hreflang checker to catch missing return links and malformed HTML silently breaking the tags.

When it's not a problem

This is a false alarm if the code happens to be valid (e.g., de or en-GB) and the tag is correctly self-referential and bidirectional — the warning may be from an overly strict validator. It is also fine when the language variant is genuinely not targeted and you intentionally omit it.

How common is it?

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