The membership of the Estonian Naturalists’ Society comprises active members and honorary members.

In general, persons with an academic education who are active in the fields of natural sciences are elected as active members, who through their activities help to fulfil the mission of the Estonian Naturalists’ Society. Active members have to pay a membership fee, they can borrow books from the Society’s library and spend the night in the Society’s guestroom at a discount. An active member will acquire the status of a lifetime member after paying the annual membership fee for 30 times or after 50 years of being a member of the Society.

The trustees are also active members, and anyone interested in nature can become a trustee. The trustees have no obligation to pay a membership fee, and lack a right to vote. Any person or organisation that supports the Society with a financial or material donation will become a supportive member.

Persons over 50 years of age, who have distinguished services in the development of natural sciences or who, through their long-time and productive activities have provided great services to the Estonian Naturalists’ Society, can be elected as honorary members.

For exceptional services, the general meeting can elect an honorary president from among previous presidents. Harald Haberman and Eerik Kumari have previously been honorary presidents, and currently this position is held by Hans Trass.