Red, white and blue represent: nation and country in turn; Pure religion; A solemn and noble royal family.
Before A.D. 19 17, the national flag of Thailand used to be a red stripe and a white elephant symbolizing an independent monarchy. (White elephants represent good luck)
However, in 19 17, when he participated in the First World War as an ally, the then King Vajirawud (Rama VI) changed the national flag to.
The current flag of Thailand.