'HK-Guangzhou Transport' ↓

The covenient and also most expensive way is：If you leave from Hong Kong, take the Hong Kong (Hung Hom train stration) – Guangzhou (Guangzhou East train station) through train. When you arrive at the Guangzhou East train station, you head for Tian He Da Sha (天河大廈) on Ti Yu Xi Lu (体育西路 - “Ti Yu” means sports, “Xi Lu” means literally West Road). It would be a 15- minute walk, or a RMB7 taxi ride without the taxi meter jumping to the next reading. From Tian He Da Sha, you can take the Airport Express Route 6 to the Guangzhou Baiyun International Airport.

The first bus departs from Tian He Da Sha at 5:30, and the last one at 21:00. The whole journey is about 1 hour.

The first bus departs from Guangzhou Airport at 7:05, and the last one at 0:10.

One-way bus fare is about RMB20, which will be collected by uniformed staff on the bus. Bus service on this route is every 20 minutes.

After the “train” way, it is time to get to the “bus” way. In fact, personally, I like the bus way best. This is because, it is comparatively convenient and not that expensive. 

But when I say the “bus” way, I mean the direct bus from Hong Kong to Guangzhou.
You can always take the train from Hong Kong to Lowu, and then take the bus from Lowu, Shenzhen to Guangzhou. Buses depart hourly from Lowu bus station, Shenzhen, next to the immigration building, for Guangzhou. But this way is not convenient, so I don’t recommend it.

There are at least a few Hong Kong bus companies operating direct bus between Hong Kong and Guangzhou. But the one I usually use is the China Travel Service (CTS) bus service. The buses are frequent, and you can get on the bus at many locations across Hong Kong island and Kowloon.

I usually go to the CTS branch in Sheung Wan for the bus. There is a booth outside the branch, overlooking the road. Get the bus ticket there and you can right away get on the bus – at the scheduled time. Wan Chai and Mong Kok CTS branches are also hot spots for getting on the direct bus.

One way journey costs about HK$100, and lasts about 2.5 to 3 hours. But do note that the drop off point in Guangzhou is different, depending on where and when you get on the bus.

Check out the CTS Hong Kong – Guangzhou bus fare and schedule here:
http://www.ctshk.com/english/bus/zhonglv.htm

Also note that since the bus will go via the Huanggang port of entry, passengers will have to get off and get on the bus twice for the immigration formality of Hong Kong side and Shenzhen side. But there will be staff on hand directing you to go back to the right bus. So no worries.

There are a few ways getting o Guangzhou from Hong Kong, or vice versa.

Let’s start from the “train” way:

a. Through Train (Kowloon, Hong Kong – Guangzhou East)

This is the most comfortable, convenient as well as expensive way. The through train departs from Hung Hom train station, Kowloon, Hong Kong and arrives at the Guangzhou East train station. Each day there are 12 trains going in one direction, and 24 trains in both directions. If it is a busy day, such as on the eve of a Chinese holiday, or a weekend, you will need to buy the train ticket in advance. Otherwise, you can usually get a seat for the following train on the same day.

The good news is that you can now buy the ticket online, or through tele-ticketing (make a phone call to book a ticket via credit card, and collect it at the train station before boarding) of the Hong Kong MTR train system.

For details of ticketing, check out Hong Kong MTR website：http://www.it3.mtr.com.hk/B2C/UserPage/sysTicketInformation_Eng.asp

The one-way journey is 1 hour 40 minutes. You go through the immigration formality (Hong Kong side and Mainland China side) at once, at where you board the train. So that is pretty convenient.

One way ticket costs about HK$190 for first class, and HK$230 for premium class.

But note that some of the through trains stop at Dongguan - just for a while - and some not.

b. Take the Hong Kong MTR train to Lowu station, go through the Hong Kong and Shenzhen immigrations, and then take the train from the Lowu train station, Shenzhen to Guangzhou, or vice versa.

The Lowu train station, Shenzhen is located just right next to the Hong Kong/Shenzhen immigration building. So the train transfer between Hong Kong and Shenzhen is not difficult.

This way is less expensive, and you can go almost at any time you want, since there is always a train every hour from Lowu, Shenzhen to Guangzhou, or Guangzhou to Lowu, Shenzhen. The train journey of Shenzhen -Guangzhou takes about 1.5 hours, and costs only about RMB36 for a soft seat. The Hong Kong train fare from Hung Hom, Kowloon to Lo Wu is about HK$32. Adding up, the whole journey from Hung Hom, Kowloon to Guangzhou through the non-through-train way is about HK$70, a lot cheaper than the the aforementioned through-train way.

The negative side, though, is that it takes longer time, and more trouble.