Choosing a structure
Three options, and the choice is mostly about resources rather than SEO theory.
Subfolders (example.com/au/, example.com/uk/) keep every market on one domain, so authority earned anywhere helps everywhere. This is the right default for almost every business, and the only one I would recommend to a company entering its second or third market.
Subdomains (au.example.com) separate markets more cleanly for large organisations with separate teams, at the cost of splitting authority. Choose it when the markets are genuinely different businesses.
Country domains (example.com.au) give the strongest local signal and the strongest trust with local customers, and they mean building authority from zero for each one. Worth it when a market is large enough to justify its own marketing programme, and a mistake when it is a test.
What does not work: parameters (?lang=au), because they fragment crawling and confuse both users and search engines, and automatic redirection by IP address, which prevents crawling of the versions the visitor is not sent to.
Hreflang, and the four errors that break it
Hreflang tells Google that two pages are the same content for different audiences, so the right one is shown and neither is treated as duplicate. It is a hint about audience, not a ranking factor, and it fails silently, which is why so many implementations are broken.
- No return tag. Every page must point to every alternate, including itself, and each alternate must point back. A one-way reference is ignored entirely.
- Wrong codes. The language code comes first, the optional region second: en-AU, not au-EN. Common invalid values are en-UK, which does not exist, the correct code being en-GB.
- Pointing at non-canonical or redirecting URLs. Hreflang must reference the final, indexable, self-canonical URL.
- No x-default. Without it, visitors who match no version get whatever Google guesses. Point x-default at the version you would want a stranger to see.
Implement it in the HTML head or the XML sitemap, one or the other, not both with different values. Search Console’s international targeting report is where errors surface; check it after launch rather than assuming.
What to localise, in order
Translation is the expensive part, so order matters. Currency, contact details and the address come first, because they decide whether a visitor believes the site is for them. Then the words that differ in meaning rather than spelling: a British visitor searching “mortgage broker” and an American searching “loan officer” want the same service under different names, and translating the page will not surface that. Then spelling and date formats. Then the full body copy.
Keyword research must be redone per market, not translated. The literal translation of your best keyword is frequently not what people in that market search, and volumes differ by an order of magnitude between countries for the same service. This is the single most common reason a well-built international site underperforms.
Other signals that actually matter
- Local phone number and address per market page, in text.
- Local currency and payment methods shown by default for that market.
- Server or CDN performance in the target country, since Core Web Vitals are measured where the user is.
- Local links and mentions, which are harder to earn than anything on this list and matter more than most of it.
- Search Console country targeting, set per property where you use subfolders or subdomains.
A note on serving markets you are not in
Working from Kathmandu for Australian, British and American clients, the practical question is credibility rather than technique: a market page needs to state plainly where you are, how time zones are handled, how invoicing works and who your clients in that market are. Hiding the location reads worse than stating it. See the Australia, UK and US pages for how I do that, and how international clients work with me.
Next steps
If you already have several market versions, an audit of the existing hreflang and canonical set is the first thing worth doing; that is part of international SEO services and the SEO audit. If you are planning a second market, decide the structure before anything is built, because changing it later is a migration with all the risk that carries: see website migration SEO.
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