Yes, travel insurance is a mandatory requirement for all Schengen visa applications, including Estonia. The policy must cover medical emergencies and repatriation with a minimum coverage of €30,000, and must be valid for the full duration of the stay across all Schengen member states. Applications submitted without a valid insurance certificate will not be processed. Airport transit visa applicants are the only category exempt from this requirement. Insurance should be obtained from a recognised provider, and the policy must clearly state that it covers the Schengen region.