Datça is a town in Aegean Turkey, located on a long and narrow peninsula, which forms the boundary between Aegean and Mediterranean Seas.
Datça is located 70-80 km west of Marmaris. The road from Marmaris (road number: D400) is the only way to arrive overland.
Although it’s possible to find direct bus services from main centres of the country, such as Istanbul during summer months; in the rest of the year your best bet is to arrive at Marmaris first, then transfer to another bus bound for Datça there.
There are ferries from Bodrum, arriving at the port on the northern coast of the peninsula. From there, Datça -which is on the southern coast of the peninsula- is a 10-15 minutes drive away.
The town (and the peninsula) is famous for its almond trees, and a local dessert made of almond and dried figs is remarkably tasty, so you may consider buying a few packages.