1. Open the browser and enter Longines Watch official website.
2. Find "after-sales service" or similar options on the website, and click Enter.
3. On the after-sales service page, look for "warranty inquiry" or similar links.
4. Click to enter the warranty inquiry page.
5. On the warranty inquiry page, you may need to enter some relevant information to verify your watch. This information usually includes the model, serial number and purchase date of the watch. This information can be found on the certificate, receipt or watch box you got when you bought it.
6. Enter the required information, and then click the "Query" or similar button to submit the query request.
7. Wait for the system to process the query request and display the results. Usually, the warranty period of your watch and other related information will be displayed.