Dress for the bureaucracy

Government offices (ราชการ) expect respectful dress: long trousers or a knee-length skirt, a shirt with sleeves, and closed shoes are safest. Shorts, vests and flip-flops can get you turned away from the transport office or quietly served last at immigration, and some offices put up signs saying exactly that. Officers notice effort: neat clothes, a smile, a สวัสดีครับ/ค่ะ, and documents in order in a folder. Bring a pen, and expect to sign every copy and write สำเนาถูกต้อง ('certified true copy') above your signature. Dressing up is not about rules alone; it signals that you take the officer's job seriously, and that tends to make everything go more smoothly.