You can buy it, just call the port directly around 3 pm. I used to run back and forth in Haikou and Beihai. If you don't know the phone number, you can call 1 14 directly, but after you call, you say you want to find the phone number for booking a boat ticket, which is the phone number of the ticket hall, not the personal one, so that 1 14 can make another profit.