Sixt Car Rental generally requires renters to be at least twenty-one years of age. However, the exact age requirements can vary based on the specific location and the type of vehicle being rented. For example, some premium or larger vehicles may have a minimum age requirement of twenty-five. Additionally, young renter fees might apply to drivers under twenty-five, which could result in an extra daily charge. It is also important to note that renters must possess a valid driver’s license and, in some cases, an international driving permit may be required. To get the most accurate and up-to-date information regarding age requirements and any applicable fees, it is best to check the specific details on the Sixt website or at the location where the rental will occur.