ENKO
SEO

Hreflang

Hreflang is an HTML attribute that informs search engines about the target language and region of each page when a website offers the same content in multiple languages or for multiple regions.

Hreflang is an HTML attribute that informs search engines about the target language and region of each page when a website offers the same content in multiple languages or for multiple regions.

Why It Matters

Without hreflang tags on a multilingual website, search engines cannot reliably determine which language version to display to which user. This leads to several problems:

  • Wrong language version shown: Korean-speaking users may see English pages in search results, or vice versa.
  • Duplicate content issues: Search engines may treat similar multilingual pages as duplicate content and exclude some from the index.
  • Ranking instability: When search engines unpredictably alternate between language versions, performance tracking becomes nearly impossible.

As of 2026, Google has explicitly stated that hreflang signals are treated as "hints." This means they are evaluated alongside other signals such as canonical tags, site structure, and content similarity. Hreflang tags alone are not sufficient — the entire international SEO setup must be configured consistently.

Implementation Methods

Hreflang tags can be implemented in three ways.

  1. HTML <link> Tag (Most Common)

Insert links to all language versions in the <head> section of each page.

<head>
  <link rel="alternate" hreflang="ko" href="https://example.com/ko/page" />
  <link rel="alternate" hreflang="en" href="https://example.com/en/page" />
  <link rel="alternate" hreflang="x-default" href="https://example.com/en/page" />
</head>
  1. XML Sitemap

Best suited for sites with a large number of pages. Use the <xhtml:link> element within the sitemap.

<url>
  <loc>https://example.com/ko/page</loc>
  <xhtml:link rel="alternate" hreflang="ko" href="https://example.com/ko/page" />
  <xhtml:link rel="alternate" hreflang="en" href="https://example.com/en/page" />
  <xhtml:link rel="alternate" hreflang="x-default" href="https://example.com/en/page" />
</url>
  1. HTTP Header

Used for non-HTML files such as PDFs.

Link: <https://example.com/ko/page>; rel="alternate"; hreflang="ko",
      <https://example.com/en/page>; rel="alternate"; hreflang="en"

Syntax Rules

  • Use ISO 639-1 language codes: Two-letter lowercase codes such as ko, en, and ja.
  • Use ISO 3166-1 Alpha-2 region codes: When specifying both language and region, combine them with a hyphen: en-US, en-GB, pt-BR.
  • Always include a self-referencing tag: The Korean page must include an hreflang="ko" tag pointing to itself.
  • Specify x-default: Set hreflang="x-default" to designate the fallback page shown when no matching language version exists. While not mandatory, Google recommends it.
  • Bidirectional references are required: If page A references page B, page B must also reference page A. One-directional references are ignored by search engines.
  • Match canonical URLs: The href value in hreflang tags must match the canonical URL of the corresponding page.

Common Mistakes

  • Missing self-referencing tags: Approximately 16% of international sites omit self-referencing hreflang tags, preventing search engines from accurately identifying the page's language.
  • Incorrect language or region codes: Common errors include using kr (a country code) as a language code, or writing en-UK instead of the correct en-GB.
  • One-directional references: Declaring hreflang on only one page without a reciprocal declaration on the other page causes search engines to ignore the signal entirely.
  • Canonical and hreflang mismatch: When the URL in an hreflang tag differs from the page's canonical URL, it sends conflicting signals to search engines.
  • Mixing implementation methods: Using HTML tags and sitemaps simultaneously is technically valid, but it increases maintenance complexity and the likelihood of inconsistencies. It is safer to choose one method and apply it consistently.