Respectful dress is always appreciated while visiting temples in Thailand. It is especially essential when visiting the Grand Palace and Wat Phra Kaew as they operate a very strict dress code! If you are not dressed appropriately then you will not be allowed entry!
These are the general rules of what should be worn and what can not be worn
1.Shorts, mini-skirts, short skirts, tight fitting trousers, tight fitting leggings and tights, (Long skirts lower than your knees are allowed.)
2.See-through shirts and blouses, as well as culottes or quarter length trousers
3.Sleeveless shirts and vests (T shirts are allowed)
4.Sandals (without ankle or heel straps) so no flip flops or thong style sandals
5.Rolled-up-sleeves
6.Sweatshirts and sweatpants, pyjamas and fisherman trousers
Further dress code notes:
Long Trousers, pants are required, not just only the knee-level ones. Quarter length trousers cannot be worn.
No hole in any part of jeans, skirts, pants and trousers should be seen.
Scarves or shawl cannot be worn to cover your shoulders, a t-shirt or long sleeved shirt must be worn
Note: long trousers and shirts are available for rent at the Grand Palace if you do not meet the dress requirements
General dress codes for temple visits in Thailand
You will find while visiting other temples in Thailand such strict dress codes are not enforced but as a general rule leg ware should be at least knee length for both skirts and shorts for both men and women, shirts should cover shoulders (can be short sleeved but not sleeveless)