The question of whether to carry your passport or leave it in a hotel safe in Bangkok is a common dilemma for travelers, balancing legal requirements with the risk of theft. Technically, Thai law requires all foreigners to carry their original passport at all times; however, in practice, a high-quality photocopy or a digital scan on your phone is usually sufficient for day-to-day activities like shopping or visiting tourist sites. Most seasoned travelers recommend leaving the physical passport in a locked hotel room safe and carrying a copy. The risk of losing your passport to a "motorcycle snatch-and-grab" or simply misplacing it in the humid, busy streets of Bangkok is often considered greater than the risk of being asked for it by the police. However, you will definitely need the original passport for official business, such as exchanging currency at a bank, checking into a new hotel, or if you are planning to visit higher-end nightlife venues that have strict age verification. If you are ever stopped by authorities without the original, being polite and showing a copy along with your hotel's business card is typically enough.