Do I need hreflang on a UK-only site?

No. A single-language site targeting one country can skip hreflang. Missing tags are not a fail in that case.

A fallback locale for users who match none of your language-country pairs. Include it whenever you use hreflang.

Hreflang Mistakes: Why UK and US Rankings Split

Hreflang Mistakes That Split Your UK and US Rankings

25 August 2026 · 5 min read · By Milvydas

Two matching gold keys on dark velvet, slightly different cuts

en-GB and en-US are sibling keys. One invalid code breaks the whole ring.

Hreflang is a set of rel="alternate" hreflang="…" link tags (or equivalent HTTP headers / sitemap entries) that tell Google which language and region a URL is for. Get it wrong and you split signals across two URLs, or show the dollar-priced page to someone in Manchester.

You only need it if you have variants

One domain, one language, one country: skip it. Two country versions of English, or a translated site: you need a complete, reciprocal cluster.

The three bugs we see constantly

Invalid codes. en-UK is wrong; the country code is GB. Use en-GB and en-US.
No self-reference. Each page must include a tag pointing at itself as well as at the other locales.
No x-default. Users who match nothing get an arbitrary version. Point x-default at your chooser or your primary locale.

Return tags

If UK points at US, US must point back at UK. One-way hreflang is treated as untrustworthy. Check both URLs, not just the homepage.

Check a URL

Paste any page into the hreflang checker. Single-language sites are marked not applicable. Sites with tags get the three structural problems above, then the rest of the full audit.