Prague is one of the safest cities in Europe, but a little local knowledge goes a long way.
It's safer to avoid the exchange booths on the street — especially around Wenceslas Square and Old Town Square. Many advertise '0% commission' but use terrible rates or charge hidden fees. Use a bank ATM (most commonly 'Česká spořitelna', 'Komerční banka', 'ČSOB'), or pay by card — the rate is almost always better. And always use local currency when using your card. Local currency, no conversion.
Use Bolt, Uber or Liftago instead of hailing a taxi off the street, especially near tourist hotspots. If you do take a traditional taxi, insist the meter is running and confirm the approximate fare before getting in. A fair ride from Old Town to the airport should be under 700 CZK.
Prague is a very safe city, but pickpocketing does happen in tourist-heavy zones: Charles Bridge, Old Town Square, and on crowded trams (especially the 22). Keep your phone in a front pocket, use a cross-body bag, and stay aware in crowds. Most incidents happen when people are distracted taking photos.
Avoid restaurants with staff standing outside trying to lure you in, picture menus in six languages, and locations directly on Old Town Square. Great rule of thumb is the price of a half-liter of a local lager: Make 75 CZK our limit, and look for 50-60 CZK range for a good deal even locals would appreciate.
European emergency number: 112 (works everywhere). Czech police: 158. Ambulance: 155. Fire: 150. You can call 112 from any phone, even without a local SIM. The operators speak English. For non-emergency medical needs, many pharmacies (lékárna) have English-speaking staff. PRO TIP: Streetlamps have six-digit numbers on them at about chest height, and operators can use those to locate you precisely.
Buy tickets before boarding — you can use the PID Lítačka app (official Prague transit app) or yellow ticket machines at stations. Validate paper tickets when you board the very first time, but never stamp them more than once. Plainclothes inspectors do check, and the fine is 1,500 CZK on the spot. A 24-hour or 72-hour pass is usually the best value for visitors.
Tap water in Prague is perfectly safe and good quality. No need to buy bottled water. Many restaurants will give you tap water if you ask ("kohoutkovou vodu, prosím"). Try not to be too mad if they don't – profit margins on food are quite low and it's the drinks that make up for it.
Prague is safe at night by European standards, but use common sense. Stick to lit streets, avoid Wenceslas Square very late (it can attract unsavoury characters after midnight), and keep an eye on your belongings in busy bars. The night tram network (numbers 91–99) runs every 30 minutes and is a reliable way to get home.