International SEO
Definition
International SEO is the strategy of surfacing the optimal version of a multilingual, multi-regional site on the search engines and AI answer engines of each language and region.
Key Technical Elements
1. Choosing a URL Structure
| Approach | Example | Pros | Cons |
|---|---|---|---|
| Subdirectory | example.com/ko/ | Consolidates domain authority | Weak regional targeting |
| Subdomain | ko.example.com | Can be operated independently | Diluted authority |
| ccTLD | example.co.kr | Strong regional signal | Cost and management burden |
Google tends to recommend subdirectories the most.
2. Implementing hreflang
<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" />
hreflang can be implemented in three ways: the HTML <head>, HTTP headers, and the sitemap. It is recommended to apply it in both the HTML and the sitemap.
3. Content Localization
Machine translation alone makes it difficult to establish E-E-A-T in each language. To increase the likelihood of being cited as a source in that language by AI answer engines, each language version should include data, examples, and sources from that market.
International SEO in the AI Era
LLMs generate answers from different source pools by language. Korean sources are cited preferentially for Korean questions, and English sources for English questions. From an AI citation standpoint, it is important that each language version independently achieves high quality.
References
- Google Search Central. Managing multi-regional and multilingual sites. https://developers.google.com/search/docs/specialty/international