You can contact Suomen Löytötavarapalvelu lost and found service at +358 (0)600 41006 regarding items left at Helsinki Airport. The service is open 24/7. The Suomen Löytötavarapalvelu office at the airport is located at Lentäjäntie 1, FI-01530 Vantaa, Finland You will most likely receive information about your items the next day. The best way to learn about the services of the company is on their own website.
If you wish to learn more about Finavia airports’ lost and found services, you can find information on the airport-specific websites.