Car rental remains the most convenient way to get around the island. In Unawatuna, you won't find any car rental agencies. So focus on Galla, or better still, Colombo.
If you want to find a car rental in Colombo without a deposit, focus on cars with drivers. It's easier, especially given the unfamiliarity with the roads and traffic in Sri Lanka. Tourists say it's not much more expensive, and it's convenient if you're going to visit some sights.
The giants such as Europcar, Alamo and others offer fairly cheap car rental at Colombo airport to take you to Unawatuna. On an average, the price of a car rental in Unawatuna ranges from 75 to 100 USD with a driver.
Be aware that Sri Lanka's roads are sometimes a real mess, there are often traffic jams, and drivers rarely follow any rules. That's why everyone recommends targeting cars with drivers. If you want to find a rental car in Colombo and Galle cheaply, book in advance online, it will save you up to 10-15 USD per day.
You'll have to pay the driver an extra 300 LKR per day for each night outside the city where you rented the car (e.g. Colombo). For overtime after an 8-hour working day, it's 95 LKR per hour.
Generally, all good hotels provide free meals and accommodation for drivers if you are traveling out of Colombo. If the hotel does not provide such facilities, the client needs to pay the driver an allowance of 1500 LKR per day.
If you are renting a car on your own, you need a Sri Lankan driver's license, which requires more than 3 years of driving experience. And you also need an international driving license/permit/certificate approved by the International Automobile Association (AA).
Foreign license holders must obtain a temporary Sri Lankan driver's license from the Sri Lanka State Registrar of Vehicles (RMV), located in Werakhera, a town half an hour's drive from Colombo. The cost of processing an application at the RMV is LKR 2500, and the process takes about half an hour. The RMV is open from Monday to Friday from 9:00 am to 3:00 pm.
