Hreflang check: do two language versions link back?
Updated
Short answer
Hreflang tells Google which URLs are language or regional versions of the same page. Pick two versions, look for both URLs in each page’s annotations, then use the language selector to open the same content.
Choose two versions of one page
A tour operator could start with one booking page in English and Spanish. Open both public URLs and confirm that they describe the same tour.
Look for both URLs in the page source
For an HTML implementation, search the source for hreflang. Both pages should list themselves and each other using full URLs. If the source has no tags, ask whether the site uses a sitemap or HTTP headers.
Try the language switch as a visitor
Switch languages and check that the same tour opens. You can practice on the guide linked below, where the English and Japanese pages point to one another.
What a rollout measured
An equipment supplier reorganized its URLs and added hreflang. Its implementation partner reported about 46% higher clicks to the UK site and about 33% higher clicks to the German site after rollout. Use your own country and landing-page data to see where visitors arrive. The published figures are percentage changes after the combined rollout.