Of course. But there is a premise that you must have a residence permit in Haikou, and the number plate in Haikou is no different from that in Danzhou. Haikou is not limited, you can use any number plate, you don't have to toss it yourself. Moreover, there are so many cars in Haikou that it is not easy to get a better number plate. It is better to get a better number plate in Danzhou.