Before entering to Thailand, all travellers must make sure that they are in possession of

1. a passport valid for at least 6 months with appropriate visa

2. proof of round-trip air ticket

3. proof of accommodation, adequate finances (see 3.1), health certificate (see 3.2)

3.1 Adequate Finances

According to the Thai Immigration Act, foreigners who fall into any of the 11 categories are prohibited to enter Thailand. This Includes "having no appropriate means of living on entering the Kingdom". 

3.1.1 holders of tourist visa, non-immigrant visa must be able to prove that they have adequate finances equivalent to at least 20,000 Baht per person (around 700 USD) or 40,000 Baht per family (around 1,400 USD).

3.1.2 On-arrival-visa tourists and holders of transit visa must be able to prove that they have adequate finances equivalent to at least 10,000 Baht per person (around 350 USD) or 20,000 Baht per family (around 700 USD).

In order to facilitate foreign tourists, Thai Immigration Officers conduct random inspection of foreign tourists' means of living upon arrival at all ports of entry. If tourists are not able to prove that they have adequate finances, the officers will then consider case-by-case whether to allow the entry. The random inspection will not take place after the tourists have been granted an entry and have passed through the Immigration checkpoints.

3.2 International Health Certificate on Yellow Fever Vaccination 

Foreign nationals travelling from/through countries which have been declared Yellow Fever Infected Areas must acquire an International Health Certificate verifying the receiving of a Yellow Fever vaccination. Upon arrival at a port of entry, you are required to present the Certificate at the health control counter located before the Immigration checkpoints.