While Brussels is a modern, tech-forward European capital, you should still carry a small amount of cash for a 2026 visit. Most major restaurants, hotels, and retail shops in the city center and around the Grand Place accept contactless payments, Visa, and Mastercard with no issues. However, Belgium has a unique quirk: some smaller, local establishments (especially "frietkoten" or chip stands and smaller bakeries) may only accept Bancontact (the local debit system) or cash, and may decline international credit cards for small purchases under €5 or €10. Furthermore, if you plan to visit the famous flea markets in Les Marolles or use public restrooms (which often have a "toilet attendant" or an automated coin slot), you will absolutely need €0.50 or €1.00 coins. For public transport, you can simply "tap" your contactless card on the STIB/MIVB readers, so cash is not needed for the Metro. A good rule of thumb for 2026 is to keep about €20 to €40 in small bills and coins in your pocket for those "Brussels moments" like a spontaneous waffle from a street van or a tip for a street performer in the Royal Park.