Tallinn Airport (Tallinna Lennujaam, http://www.tallinn-airport.ee/en/) is conveniently located at the edge of the town. The conference venue is only about 4 km away. Tallinn offers convenient direct flights to many important European destinations like Amsterdam, Brussels, Frankfurt, Helsinki, Copenhagen, London, Munich etc.
Arriving by Ferry
Tallinn is well connected to Helsinki, Finland, via multiple ferries per day (traveling time roughly 2 hours, one way ticket about 30 Euros), look at http://www.portoftallinn.com/ or https://laevapiletid.ee/.
International bus lines (Lux Express and Ecolines, look at http://www.bussijaam.ee/en/) offer bus connections between Tallinn and many European cities. Most useful might be Tallinn – Riga (traveling time roughly 4.5 hours, one way ticket about 25 Euros).