Marathon is 42 km northeast of Athens. The most practical option from the city is the KTEL bus from the Mavromateon terminal in central Athens (near Pedion tou Areos park); buses run several times a day and take about 1 hour 15 minutes. The bus stops in Marathon town near the main square, from where the museum and tumulus are about a kilometre away by foot or taxi.
By car from Athens, take the coastal road via Rafina or the inland route via Nea Makri; the drive takes 45 minutes to an hour depending on traffic. A taxi from Athens will cost around 50-70 euros each way. There is no public transport within the Marathon area, so having a car or hiring a taxi for the day gives much more flexibility for combining the tumulus, museum, lake, and beach.