Generally, renting a car is easy in Singapore. The regulations largely lie on the part of the car rental companies. In some car rental companies, you can rent a car as long as you have a license. For others, there are varying requirements.
Age Requirement: It depends from firm to firm. The usual age requirement stated is at least 21 years old. This is the age whereby one is legally fit to sign a valid contract. However, one can still find car rental firms that rents out cars to drivers as young as 18 years old. There are also firms that rents out to individuals above 25 years old. These are usually those that rents out premium cars.
Driving Experience: The usual driving experience required is one year. This is due to the insurance policy of the cars. Some firms rent cars to new drivers but at a higher rate and/or if any damages are incurred, the insurance covered is much lesser.
These are the 2 restrictions to car hirers in Singapore. Drive Safely!