Even though the islands are 18, they are well connected with roads ands bridges, ferries and tunnels. With public transport it almost possible to reach all of them.
It’s definately most convenient to rent a car to get you around the islands, but public transport busses and ferries are also available.
All timetables for busses and ferries are found here: www.ssl.fo
Timetable and fares for Atlantic’s helicopter route are found here: www.atlantic.fo