You can go to Cha Am by bus from Sai Tai Bus Terminal (Southern Bus Terminal) in Bangkok or by train from Hua Lamphong Railway Station or from Bangkok Noi Railway Station.
I prefer travel by train, relax and enjoy view along the way. Cha Am Railway Station (or Ban Cha Am Station) is a small station, only slow train stop by, all the fast trains will pass by to stop at next major station, Hua Hin Station.
Cha Am Railway Station is about 2 Km. far from front Cha Am Beach. When you reach there and feel too lazy to walk, motorbike taxi waiting for you there in front of the railway. I spent around 40 Baht for slow train (Ordinary Train) from Bangkok to Cha Am and 20 Baht for motorbike taxi to front beach.
Well, on the ride, the taxi did try to offer me selections of accommodations too. If you are looking for cheap accommodation, kind of walk-in, dont worry, and dont have to hurry to take their offer, many cheap places along front beach road, mostly in the northern part. You can just take a walk and choose the place you like, some places they even have a sign in front to show rate of the room (the cheapest I've seen is 200 Baht/night for non air-con room).
The chances are you will probably be coming from Bangkok to Cha am and it is a fairly simple process. There is a train service but it is infrequent and not as quick. The bus departs from the new Bangkok Southern Bus Station which is a bit of a pain to get to (see seperate tip) but once there buying a ticket is simple. The ticket for the journey costs 130B for ordinary and 150B for air-con. I got an ordinary bus as the air-con on Thai buses can be Arctically cold. From Bangkok it is about three hours and you will get a rest stop on the way.
Cha am is not a large place walking is quite easy although another popular option is to rent a bicycle. Tehre are various places along the beach road that will rent them with the usual price being about 20 baht per hour. For some reason I never quite fathomed the vast majority of the bicycles on offer are a pretty garish baby pink colour. Should you be with a group of friends there are tandems widely available and even bicycles designed for three or four people. These seem to be very popular with Thai kids who pedal up and down the seafront laughing and shouting to wach other.
A good and quick way to get to and from Cha Am is by mini van.You can catch the van at Victory Monument ( exit BTS station turn right and go down the stairs) the vans are parked beside a shopping mall..The fare is 160 baht per person and the van seats about 12 people.Comfortable trip.
You can get to Cha Am easily by coach at the Southern Bus Termanal .However there are two operators (the good bus & the crappy bus).The good one ,the buses are in good condition and will take you to Cha Am bus station which is close to the beach.The crappy buses are old and run down,broken seats ,poor air-conditioning,very slow and stopping to drop off /pick up people many times. People even come on asking for buddist donations and selling food.This bus does not tale you to the beach but drops you off at the turn off.You then have to catch a motorcycle taxi to the beach.
Taxi or limousine from Bangkok hotels or Bangkok Airport to Cha Am
Some trains stop at Cha Am Railway station, all trains on the route stop in Hua Hin from where you can take a taxi for the 15-20 minutes to Cha Am
SGA Aero now have 4 flightds per day from Bangkok to Hua hin Airport, the airport in Hua hin is just north of the town and it takes perhaps 10 to 20 minutes to reach your Cha Am hotel, in fact many Cha Am hotels are quite near to Hua Hin anyway. The flight is in a 12 seater aircraft, some Cha Am hotels can arrange to collect you from the airport
From Kuala Lumpur to Cha Am - either fly to Bangkok and then take a taxi to Cha Am. From Penang there is a daily train service ( see under the Train travel tips )
Travel by train from Malaysia to Hua hin and Cha Am - by KTMB / Thailand Railways with the daily service from Butterworth ( Penang ) to Hua Hin Thailand and then a taxi the 15-20 minutes to Cha Am.