Are there 24-hour self-service laundromats in Bangkok?
Yes — several chain laundromats run 24/7. The most common chains: Aim's Wash (multiple locations including Phra Nakhon Khao San area, Sukhumvit Soi 22, Lat Phrao), Speed Wash (Sukhumvit, Asoke), Coin Laundry (Thonglor, Phrom Phong), Tex Laundromat (Silom Soi 4). 24-hour means actually 24/7, not 'shops open till midnight.' Card-only payment in late-night hours (no cash). Security cameras everywhere. Generally safe to use overnight if you stay with your laundry.