Three and a half hours. Best to rent a car because the taxi will charge you about the same as a day's rental. Of course, you could share a taxi and split the cost. Best is to land at Punta Cana. If you do land in Santo Domingo, then spend a night in the city, and then take the bus out to Bavaro from Santo Domingo, much, much much cheaper than a taxi. Taxi could cost US$100. Think a bus is about US$4. Taxi to SD is about US$25 unless you can grab a cab with a local, then it is about RD$600 (about US$12).