Loose clothing is worn throughout, since the work uses no oil and moves the body through space.
In 📝Thai Bodywork the receiver stays dressed in something that can stretch, fold, and be palmed through. Tight jeans or a skirt that cannot move will fight the stretches. The rule is practical, not a dress code as a moral claim, and not a hygiene lecture. If clothing cannot be loose that day, the session is adapted rather than forced.
Clients feel able to be moved. Skin-to-skin oil work is a different modality.