Chiang Rai is in the far north of Thailand. From Bangkok, the fastest way to come is to take the plane because by bus it take around 12 hours. Buses depart very regularly from the Bangkok Northern Bus Terminal (Mochit) in Bangkok. Note that from Chiang Mai, only the company Green Bus offers buses to go to Chiang Rai. They are no other choice and no minivan connecting the two cities. Therefore I strongly recommended you to book your tickets in advance, at least the day before your departure (online booking here but note that tickets are only on sale 4 weeks before the departure date) otherwise you will probably have to wait at least 2 hours time before having seat in a bus. Buses leave from Chiang Mai Bus Terminal 3 (just opposite to the Arcade Bus Terminal). The train does not go to Chiang Rai, it does not go further than Chiang Mai. Note that there are now VietJetAir flights between Chiang Rai and Phuket.
local_taxi
Taxis / Cars / Vans withe driver to go to Chiang Rai
WARNING: many buses can only be booked 30 days before depature tops. They won't be displayed in the results on our transportation booking partner's website if not bookable yet.
Apart from flying to Bangkok or Phuket, you can only leave Chiang Rai by bus. The nearest railway station is in Chiang Mai, the train does not go to Chiang Rai. The city has two bus terminals, Terminal 1, in town, for trips in the province (only Green Bus offer long-distance departures from this terminal) and Terminal 2 for long distances. A bus ride to Bangkok takes at least 11 hours, so the plane is strongly recommended. There are otherwise buses to Sukhothai or Phitsanulok and some other destinations without going to Chiang Mai first. To return to Chiang Mai, since the only possibility is to take a bus from the Green Bus company, if you do not want to end up waiting 2-3 hours at the bus terminal I advise you to buy your seats in advance, at least the day before you leave (online booking possible here but note that tickets are only on sale 4 weeks before the departure date). There are different levels of comfort, the cheapest bus (no toilet) leaves at 9:30.
WARNING: many buses can only be booked 30 days before depature tops. They won't be displayed in the results on our transportation booking partner's website if not bookable yet.
The train is the cheapest way to travel in Thailand especially in 3rd class. This is also where the contact with the population is the most interesting and incredible...
Taking the plance to travel in Thailand is often not that much more expensive than the bus especially with the numerous specials offers and it is so much faster !