Should You Take a Boat from Sanya to Haikou to Xuyun, or Wait Until the Next Day?
Sanya is a southern Chinese island, separated from mainland China by the Qiongzhou Strait. The main transportation for entering and exiting Hainan Island is by train and plane. When going to the island, there are many discounted air tickets, which are very cheap, but when returning, the ticket prices return to normal and are quite expensive, and there are almost no discounted tickets, so many budget travelers buy discounted air tickets to go to the island and then take the train to leave the island, but you will find that the people who take the train to leave the island are particularly numerous, and the train tickets are difficult to get, like the Spring Festival rush hour ticket purchase is very difficult.

However, a part of people take alternative routes, that is, first take a car or bullet train from Sanya to Haikou. Note that the frequency of bullet trains from Sanya to Haikou is very high (formerly D-letter trains, now all C-letter trains), and there are many trains, and the ticket prices are between 83 and 128 yuan, which is easy to buy, and takes about 1 hour. There are also many car tickets, which are basically easy to buy, unlike the train to leave the island that is difficult to buy. Then take a boat from Haikou.

Take a bullet train from Sanya to Haikou in the afternoon, and arrive in Haikou in the afternoon. Then you can take a bus from Haikou to Xuyun Haian Port, and then take a boat from Xuyun Port to leave the island. Since we started from Xuyun Port, Xuyun Port is relatively close to Haikou East Station, so it is recommended to buy train tickets from Sanya to Haikou East.
Note:
When you arrive at Xuyun Haian Port, you will find that there are many large buses in the port, the most luxurious one goes to far away Zhanjiang, of course, there are also buses to other places, when departing from the port, one by one private car owners come to solicit business, asking if you want to take a car to Xuyun. Haian Port and Xuyun Port are different, Xuyun Port can be said to be in Haikou City, has buses, traffic is very convenient, Xuyun Port has no accommodation, if you arrive in the evening, you can only take a private car to Xuyun, the car fare is 15 yuan, and the distance is quite far, all local business owners solicit business, there are motorcycles and minibuses.

Haikou and Xuyun are very different, even though they are only separated by the Qiongzhou Strait, Haikou's basic services are well-developed, there are many hotels, guesthouses, and guesthouses are relatively affordable, with guesthouse prices as low as 39 yuan, it is quite affordable, and Haikou's consumption is not high. Xuyun is a small county with accommodation basically hotels (the cheapest accommodation is about 60 yuan, conditions are relatively poor), there are no guesthouses, and consumption is not high.

So, do you want to go directly to Xuyun from Haikou in the afternoon?
My suggestion is not to, there are many boats from Xuyun to Haian, and the boats are big and can accommodate many people, the boat management is also relatively loose, for example, if you buy a boat ticket for tomorrow, the online display has no ticket, you can buy a ticket for the day after tomorrow, as long as you buy a ticket, you can board the ship tomorrow.
After arriving in Sanya, you can stay in a guesthouse for one night in Haikou, and it is recommended to choose a guesthouse that is close to Xuyun Port, and then you can leave at 6:00 and 7:30 the next day, and arrive at Xuyun at 9:00, have breakfast in Xuyun, and visit Xuyun County, which is actually a small county with nothing to visit, then walk to Xuyun Railway Station.

Xuyun Railway Station is a small station, and it is quite far from the county, and there is no bus system. Last time I walked all the way to the station from the city, Xuyun has a train going to Guilin, the train number is K458, departing at 17:33, and arriving in Guilin North at 3:47 the next day. If you want to go to Guilin to see the scenery, you can directly buy a ticket to Guilin.

Tip: K458 passes through Guilin, it also passes through Changsha, sometimes the train tickets from Guilin to Changsha are not available online, maybe it's just out of tickets, so you can buy a train ticket to Guilin and board the train to Changsha for replenishment. In fact, it's better to arrive in Changsha, because it arrives at 11:19 the next day, which is not as tiring as staying in Guilin to disembark at midnight.