Vaccinated people from anywhere are exempt from testing and isolation.
People who have undergone a COVID-19 vaccination programme (ie they've gotten both shots of either Pfizer, Moderna or AstraZeneca vaccine and two weeks have passed since the second dose; or they've gotten the single-shot Johnson & Johnson vaccine and two weeks have passed since) within the past year do not need to self-isolate or test for the coronavirus.
Also, people who have suffered from the novel coronavirus and no more than a year has passed since they have been declared cured, don't need to test or self-isolate. These exceptions apply to people arriving from anywhere in the world.
More detailed information: https://www.visitestonia.com/en/why-estonia/coronavirus-and-travelling-to-estonia