In Thailand they don’t shake hands, (even if it’s done towards foreigners) and don’t kiss each other, They use Wai (ไหว้) to greet, to thank and to show respect.
But Wai is not like a hello because you don’t necessarily do it every day and to anyone.
Basic Thai greetings: Sawasdee
If you want to say hello in Thailand in a polite way, you must say these words and do the Wai according to the age and status of the person (see below).
If you are a man, whether you are talking to a man or a woman, you say Sawasdee krab.
If you are a woman, whether you are talking to a man or a woman, you say Sawasdee ka.
If you are a man, but you consider yourself a woman (katoey), then you can say Sawasdee ka.
If you are a woman but you consider yourself a man (tomboy) you can say Sawasdee krab.
Wai meaning: the different levels of Thai Wai
In Thailand, older people and social categories are respected, so the level of the wai will depend on these two factors.
Hands joined at the level of the lungs, to respond to a Wai given by someone younger than you or from a lower social category:
Hands joined at the chin level, to respond to a Wai given by someone of the same age and social class:
Hands joined at the nose, to be done first to older people or people of a higher social level:
Hands joined at the forehead, for monks or members of the royal family:
When and how to do Wai or greetings in Thailand
As a foreigner, it doesn’t matter if you don’t do Wai; Thai people learn to do it from childhood, and for them, it’s an acquired reflex.
For us, it’s sometimes difficult to know when to do the Wai, and to think about the level of joined hands to do.
If you have trouble, you can answer with a fast Wai no higher than the chin for everyone.
An important person, so as not to lose face in public, will come to shake your hand if you do not give him the Wai.
It is polite to answer the Wai, even the one made by a child but it is not mandatory to answer the Wai given by the employees of a business unless it is a person you know; generally, they do not expect an answer, they just do their job.
In both cases (children and employees), a nod and a smile are enough.
Do not do the Wai first to younger people (except monks, bosses or members of the royal family) or every day to older friends.
We do the Wai first when we deal with or are introduced to someone older or of a higher social class.
And we respond to the Wai given by people of younger age and lower social class.
It is useless to do the Wai to your friends and family every day if you see them often, you have to do it, for example, before a long trip and on the way back.
We also do the Wai to thanks for help or a gift.
You have to do the Wai for monks, even younger when you want to talk to them and they will not answer because they do not have the right to do the Wai to laypeople, this is part of the rules they must respect.
It is important to do the Wai to the owners of the house to which you have been invited.
Thai Wai explained in a video.
A nice video to understand how to do the traditional Thai wai and basic Thai greetings:
In Thailand, even dogs do the Thai Wai
If you want to know more: Wikipedia