The Subte (metro) has six lines running 5:30am–11:30pm weekdays and accepts contactless Visa/Mastercard and Google/Apple Pay since late 2024. Buses (colectivos) run 24 hours and require a SUBE rechargeable card (available at kiosks, Subte stations, and tourist centers for ~1 USD). Avoid both during rush hour: 7:30–9:30am and 5–7:30pm.