It would be a shame to travel all the way to Tallinn and not be able to take at least one day trip and see the out-laying sights of Estonia. If there is not enough time to leave the immediate Tallinn area, hopefully at least one guided tour through Tallinn can be taken.

Following are some day trips and guided tours:

Helsinki and Lahemaa National Park Day Trips A day trip to Lahemaa National Park, in the North of the country is a great way of spending some time away from the urban hustle and bustle. You will have the opportunity to admire the Estonian nature, as the park that stretches on 725 km² (out of which 250.9 km² of sea) is home to waterfalls, rapid streams, forests and lakes. Besides, Lahemaa National Park is home to historic landmarks (Palmse and Sagadi Manors) and to the Forest Museum. Tallinn is connected with the Finish capital city by regular ferry buses. In 2 hours you  will get to Helsinki and you can return to Tallinn the same day.

City Bike Tours and rental: They offer tours all year round. Focusing on bicycle activities (rental, Welcome to Tallinn bicycle tour and Lahemaa by Bike tour), they offer also nature tours and secret tunnels tour in Old Town of Tallinn. Not so much about traditional big groups and by the book guiding. Instead small groups and personal touch. Old Town walking tour is combined with "Secret Bastion tunnels". Lahemaa Tours can be done by bike (tehy offer transfer and bicycles with GPS) or walking in the nature and visiting some historical sights. In summer also fun tricycle with 7 seat rides alongside city, called Conference Bike. 

Tallinn Traveller Tours: Day trips all year round. They offer travelers an alternative way to explore Tallinn and Estonia through the eyes of local youth organizing Day Trips in small groups to Lahemaa, Paldiski, Narva and Haapsalu, Shore Excursions, Walking Tours, Bike Tours and Pubcrawls in Tallinn and around. They have selected all their guides from young educated locals who have born and lived in Estonia. The company started as a student summer project back in 2006 and is still carrying the young energetic vibe.   

EstAdventures: This small outfit offers a range of tours that are a really fun way to experience Estonia and all the culture and history that goes along with it. There are day trips to Lahemaa, Estonia's stunning national park, half day "Communist Estonia" trips to Paldiski, the former soviet naval base, and some really unique tours to the East and West of Tallinn that are designed for people who like to get out off the tourist bubble. They also have a range of interesting walking tours, which run daily. There are Old Town Walking Tours, a Soviet Tallinn Tour, and some really social, enjoyable tours which have stops at pubs. 

Hop-On and Hop-Off Tour of Tallinn: This is a guided tour that allows passengers to get on an off a bus in many different locations around Tallinn. There is a narration during the tour that is available in many languages. This is a great tour because it takes tourists to places they might not ordinarily go on their own. The tours can last anywhere from a few hours to an entire day. 

Prangli Island Day Trips: Full-day regular tours, operated three times a week in summer, take you to Prangli, the small island very close to Tallinn, but still untouched by mass-tourism. The Estonian island is  presenting an authentic fishing-village atmosphere together with untouched sand beaches and pine forests. The all-inclusive package tour comes complete with transfers from Tallinn city centre, ferry transport, a truck - excursion with an English speaking guide, a museum visit and lunch. This tour makes a wonderful change from the typical Tallinn city break and can be a good opportunity to know more about Estonian culture and traditions! They sell tickets online and in hotels.

Tallinn Official Sightseeing Tour: This tour is the best of both the walking and bus riding worlds because it combines the two. The tour normally lasts about two and a half hours and it takes participants all over the Tallinn area and covers many of the interesting facts about the town.