Most travelers to the Dominican Republic require a passport along with either a Tourist Card or visa. Tourist Cards can be purchased at all airports upon arrival for US $10. The cards allow a stay of up to 60 days. You must return it to Immigration when you leave the DR. If you lose the card during your visit you'll be required to purchase a new one to exit the country. After passing through Immigration, you'll pick up your luggage, go through Customs and exit the airport.
There are 7 international airports in the DR. For most destinations on the south coast, visitors fly into either the Las Américas International Airport (SDQ), just outside of Santo Domingo, or to the Los Cajuiles Airport in La Romana. For destinations on the north coast, most visitors fly into Puerto Plata Gregorio Luperon Airport (POP), but the Cibao International Airport (STI) in Santiago also receives some regularly scheduled flights, mostly from the US. For destinations on the west coast, visitors fly to Punta Cana International Airport (PUJ). The domestic airports, Herrera Airport in Santo Domingo, and El Portillo Airport in Las Terrenas, sometimes receive international flights.
The airlines that service the DR are constantly changing. Check internet travel sites or a local travel or tour agent to ensure you get the most up-to-date and complete list of flight options available to your destination for the time you plan to visit.
Spanish is the main language and the average age of the 9 million population is 24. The Dominican peso is the currency, and the exchange rate varies daily but is typically around 16-17 pesos to the dollar. Since it's not possible to find Dominican pesos outside the country, plan on bringing US dollars: these are the most readily-accepted and exchangeable foreign currency in the country. Banks are the best place to change money, and be sure to keep your receipts because you can exchange 30 percent of the pesos back into dollars on departure.
The Dominican Republic's bus companies provide an excellent, inexpensive service over much of the country. You can ride from town to town for as little as $.35. Lines move quickly, there's plenty of room for luggage and the trips are comfortable. The informal network of guaguas - ranging from acceptable minibuses to rattletrap vans - are even cheaper and more extensive. They cover every inch of the DR, but in most cases, you should be prepared for some discomfort and you may have trouble fitting in much luggage. Taxis are another option for getting around the cities, and by foreign standards are relatively cheap.
Car rental is common but more costly: usually at least $45/day. However, domestic airlines are reasonably economical, and can make sense if you're not exploring much beyond the main cities. There are also numerous tour operators in Santo Domingo, Puerto Plata and the all-inclusive resorts who can organize individual itineraries that include transport.
FYI, it is considered offensive to enter a church or temple inebriated or wearing shorts.