Estonia is a well-developed country with a thriving private sector and modern technology. Tallinn is the capital city and has an active public transportation system composed of trams and buses very similar to the kinds of transportation we see in the U.S.A. However, Estonia does not use underground metros like the major cities in the U.S.A. and Europe.
The two most popular ways to travel between big cities in Estonia are by train and by bus. Estonia is well-connected by commuter lines, and it has its own versions of Amtrak and Greyhound. Personally, I love to travel on the Lux Express bus, a very posh line that includes wifi, movies and free coffee, but the train is a half hour quicker than the bus (if timing is important to you). I have also taken the smaller buses to the countryside, and I have found that the stops are quite well-labeled and easy to navigate, although none of the directions are in English!
An essential part of travel here are fishing boats and ferries because Estonia has over 2,000 islands. Ferries take passengers to the most popular islands, like Saaremaa, and smaller boats will take visitors to places like Kihnu (an island run by women!).