Technical SEO: hreflang audit for UK multilingual sites

What to take away

For a technical SEO audit, treat hreflang as a signal, not a fix. Every language and country version needs a self-referencing tag and a return link from each other version.
Most UK failures come from invalid pairings or from reciprocity that breaks when a page is redirected.
Use x-default for visitors who match no listed variant, usually a language selector or the global English page.
Audit quarterlyexport the tag matrix, verify it against crawl and log data, then recheck canonicals on every variant.

Why hreflang goes wrong on UK multilingual sites

Hreflang annotates page alternates. Google Search Central's “Tell Google about localized versions of your page” explains how to signal localized URLs. It does not merge ranking signals the way a canonical does, and it never overrides a redirect.

After Brexit, plenty of UK retailers kept one English page for the whole EU while adding German and French translations. Irish searchers then compete with British ones for identical en-GB copy, and Irish delivery and returns terms go unexplained.

Compare Google Search Console's country-filtered performance data with the countries included in each hreflang cluster. UK-wide ONS figures describe the industry, not how this site's pages perform in other markets.

Language and country pairs that need separate tags

Use language subtags from ISO 639-1 and, where needed, region subtags from ISO 3166-1 alpha-2, in line with BCP 47 (RFC 5646). For example, en-GB is valid, while en-UK is not: the UK region code is GB, not UK. An HTML alternate can be written as <link rel="alternate" hreflang="en-GB" href="...">. Keep en-GB and en-IE apart when prices and legal wording differ, and use a bare language code such as en only when one English page truly serves everyone.

Hreflang tag variants compared

Page variant

UK English storefront: en-GB
Irish storefront: en-IE
Generic English: en
Default: x-default

Tag

UK English storefront: Sterling pricing, UK delivery
Irish storefront: Euro pricing, EU returns terms
Generic English: One page for all English speakers
Default: Language selector or global landing page

Typical job

UK English storefront
Irish storefront
Generic English
Default

x-default is not a language. It marks the page to show when nothing else matches, so pointing it at the UK homepage by default will misdirect European visitors.

Country targeting depends on more than tags. Currency, delivery promises and local contact details reinforce the same signal, and they are what searchers actually check.

How to run the audit

Use Screaming Frog SEO Spider or Sitebulb to crawl the site, then export every URL and its hreflang cluster from the sitemap or template, with the canonical beside it.
Check that each variant returns a 200 status and is not blocked by robots.txt or a noindex tag.
Confirm every tag uses a valid language subtag and a recognised region subtag.
Test reciprocityif one page points to another, the second must point back.
Check self-reference, including the x-default target, which should name itself too.
Compare each tag with the canonical on that page, because a canonical pointing outside the cluster breaks the link.
Re-crawl after release and confirm the tags appear in the rendered HTML, not only in a script variable.

Verifying the cluster with crawl and log data

Crawlers that execute JavaScript reveal whether your tags survive rendering, which matters on sites built as single-page applications. Use Screaming Frog SEO Spider's JavaScript rendering or Sitebulb's rendered crawl to check the final HTML. Google Search Central's “How to consolidate duplicate URLs” guidance explains why a conflicting canonical can undo the cluster.

Server logs give the other half of the picture. Screaming Frog Log File Analyser can show whether search engine crawlers reach each variant, instead of trusting a template that may not render. Repeat the log analysis after release to confirm access to the live URLs.

Reporting the fixes without breaking rankings

Change one cluster at a time and re-crawl before moving on. Removing a return link can leave a group of pages competing for the same query, so keep a before and after record of which URL ranks in each market. Note the date of every change, because country-level visibility often shifts over several weeks rather than overnight.

Keep a simple spreadsheet: URL, market, tag value and the date it changed. It makes the next quarterly audit much faster.

Search Console performance reports can be filtered by country. Once a site carries hundreds of variants, it is quicker to export Google Search Console bulk data than to click through property by property.

Common questions

Does hreflang replace a canonical?

No. The canonical picks one URL to rank; hreflang points to alternates for other languages or regions. Where the two disagree, the canonical usually wins and the cluster stops working.

Can en-GB and en-IE share the same content?

They can, but only if the pages mean the same thing to both audiences. Different pricing or returns terms justify separate URLs, because those differences change what the searcher needs.

Where should x-default point?

At the page you want shown when no language or region variant matches, such as a language selector or a global English page. Pointing it at the UK homepage is only correct if that page really is the default for everyone.

How often should the tags be checked?

Quarterly is enough for most sites, and always after a replatform, a URL change or a new country launch. The check is cheap: a crawl, a sitemap export and a country filter in Search Console.