What kind of Thai girl wears a bikini at the beach?
There is still a shocking high number of Thai women that would never consider doing this.
I think if a Thai woman is with a foreigner, has foreign travel experience or is young and active on social media, there are likely to wear a bikini on the beach.
Other traditional Thai women, professional office women, rural women, may not be so outgoing and willing to try.
Women that leave in beach resorts like Samui and Phuket, yes.
Bangkok city girls and office women. Maybe not.
Tradition Thai women will feel uncomfortable doing this around strangers.
It is up to each woman to make her own choice.