How many and what are the holiday days in thailand?

Usually about 15 days in a year. If you use your own computer and using Microsoft Outlook, you can even install Thai holidays into your calendar.

Any government site will also announce the holiday including Bank of Thailand for Banking holidays. This is for 2009:

1. Thursday 1 January New Year's Day

2. Monday 9 February Makha Bucha Day

3. Monday 6 April Chakri Day

4. Monday 13 April Songkran Festival

5. Tuesday 14 April Songkran Festival

6. Wednesday 15 April Songkran Festival

7. Friday 1 May National Labour Day

8. Tuesday 5 May Coronation Day

9. Friday 8 May Wisakha Bucha Day

10. Wednesday 1 July Mid Year Closing Day

11. Tuesday 7 July Asarnha Bucha Day

Effective from B.E. 2550 onwards, the Asarnha Bucha Day is prescribed as a holiday, in replacement of the Buddhist Lent Day

12. Wednesday 12 August H.M. the Queen's Birthday

13. Friday 23 October Chulalongkorn Day

14. Monday 7 December Substitution Day of H.M. the King's Birthday

(On Saturday 5 December)

15. Thursday 10 December Constitution Day

16. Thursday 31 December New Year 's Eve