National Dresses

Man

For men, the traditional dress is trousers with a "seua phra ratchathan", a short-sleeved shirt (long-sleeved for formal occasions) with a high collarless neck. On formal occasions, a cummerbund is tied around the waist.

Woman

Thai Chakri

Thai Chakri is a formal and elegant wear, normally produced using the Yok weaving technique (Yok creates additional thickness within the fabric without adding supplementary threads. Often gold and silver threads will be used as the well, making silk produced this way particularly expensive) The Pha-sin a full length wraparound skirt with two pleated folds in the front called Na Nang.

Thai Boromphiman

Thai Boromphiman, also a formal evening attire, comprisce a long sleeved blouse which is either buttoned at the front or the back. The blouse is tucked beneath the Pha-Sin with its front pleats (Na-Nang). The fabric is brocaded to create a highly luxurious look and feel. The blouse is round-necked. The skirt is ankle length. The skirt and blouse are sewn together like a one piece dress of which style is suitable for a tall and slender wearer. It can be worn for formal or semi-formal ceremonies such as the League Ceremony or royal functions. Royal decorations are also worn.

Thai Siwalai

Thai Siwalai, a formal evening costume, is quite like Thai Boromphiman, but it has a shawl over it. It is worn for royal ceremonies or formal functions.

Thai Dusit

Thai Dusit is a wide-necked and sleeveless brocaded dress. The skirt and blouse can be sewn together. It can be worn for evening ceremonies in place of Western-style clothes. The Yok silk fabric is used. Either Thai or Western-style ornaments can be worn.

Thai Chakraphad

Thai Chakraphad is a Thai dress with a shawl like Tahi Chakri. However, it is more conservative and official. The upper part has a pleated shawl cover a thicker shawl with full embroidery on the upper shawl. It can be worn for royal or national ceremonies.

Thai Amarintra

Tahi Amarintra is evening attire, made of brocaded fabric. With this style, the wearer does not have to wear a belt. The blouse can be wide and round necked and the sleeves cover the elbow. The beauty of this dress is its textile and ornaments. It can be use for an evening dinner or at the Royal Birthday Procession. The royal decorations are worn.

Thai Chitralada

Thai Chitralada, with its brocaded band at the hem of the Pha-Sin, is a daytime ceremonial dress. It can be worn with a long sleeved silk blouse, with the front opening attached with five ornamental silver or gold buttons. The Pha-Sin is a casual wraparound. It can be worn to a ceremony that is a not too informal such as welcoming the official royal guests at the airport. Wearers do not need to wear royal decorations but the color and style should be appropriate.

Thai Reun-ton

Thai Reun-ton is the most casual of all eight styles. It comprises a horizontally or vertically striped silk or plain-coloured Pha-Sin with a patterned band at the hem, sometimes folded to one side, The collarless blouse that goes with it is separated from the ankle-length skirt. The sleeves are elbow length, and the blouse has a front opening. It is suitable for casual and non-official functions such as Kathin Ton, the religious ceremony of the conferring of royal offerings to monks.

Extracted from Wikipedia: Thai Dress