Surface protection of highly stressed components used in aviation or energy production is of great interest, especially extending the operation ranges in oxidative high-temperature environments. Here, transition metal (TM) ceramics are a suitable class to resist such conditions. Combining a high temperature stable ceramic, such as transition metal diborides, with the excellent oxide former Si was proven to result in coatings with outstanding oxidation resistance, tested up to 1500 °C. Various TM-Si-B2±z (TM=Ti, Cr, Hf, Ta, W) films were sputter deposited and subsequently oxidized in a DTA/TG setup to study the oxidation kinetics. Above certain Si contents Ti-Si-B2±z, Cr-Si-B2±z, and Hf-Si-B2±z exhibit strongly retarded oxidation kinetics with kp values being below 10-11 kg2m-4s-1 at 1100 °C. Long term oxidation tests at 1200 °C (up to 60 h in ambient air on hard substrates) confirmed the protective ability of such coatings, i.e. with Hf0.20Si0.23B0.57 exhibiting an oxide scale thickness of only 1.5 µm after 60 h. Along with a broad set of high-resolution characterization techniques the study introduces this new class of hard coatings for oxidation protection at ultra-high temperatures.