Yes, Guangzhou Airport provides 24-hour foreign currency exchange service. No matter whether you fly during the day or at night, you can change foreign currency at the airport. Airports usually have multiple exchange counters, which are convenient for passengers to exchange foreign currency at any time. However, I want to remind you that only a few counters may open late at night or early in the morning, and there may be some delays or queues. Therefore, it is a better choice to plan the time and amount of foreign currency exchange in advance during the trip.