Influence of hydrogen at pressures up to 35 MPa (and absorbed hydrogen with concentration up to 32,7 ppm) on the nanopore nucleation, crack initiation and propagation in Ni–Co superalloys for disk application with different chemical composition and tempering modes has been investigated. It was established that under the influence of gaseous hydrogen, the tensile strength, true fracture stress, relative elongation, and reduction of area of disk alloys samples decrease both at room and close to operating temperatures (1073 K). The cyclic durability of the samples under the influence of prolonged exposure to high pressures and temperatures in the hydrogen gas environment decreases by about 3 times.We have discussed the mechanisms of hydrogen-assisted nickel-cobalt superalloys fracture on mesa-, macro-, micro-, and nano-levels.