Käsmu is 80 km east of Tallinn, an easy 80-minute drive on the well-maintained Tallinn–Narva highway (E20) followed by a 15 km side road through Võsu. There is no rail service.
Public buses run from Tallinn's central bus station to Võsu, the larger neighbouring village, several times a day in summer; from Võsu it is a 5 km walk or short taxi to Käsmu. The bus service is reduced in winter. A car is the easier option year-round and gives you access to the surrounding Lahemaa National Park — the coastal forests, manor houses at Palmse and Sagadi, and the bog walks further inland.