High-resolution tandem mass spectrometry (HR-MS²)-based metabolomic studies of Amycolatopsis saalfeldensis, isolated from the “Saalfelder Feengrotten” caves in Germany, led to the isolation of three ribosomally synthesized and post-translationally modified type II thiopeptides, saalfelduracin B–D (1–3) and the known saalfelduracin A (4). The structures of all four compounds were determined by comparative two-dimensional NMR analysis and high-resolution tandem mass spectrometry.