  We investigate the reach of the LIGO/Virgo/KAGRA detectors in the search for
signatures of first-order phase transitions in the early Universe. Utilising
data from the first three observing runs, we derive constraints on the
parameters of the underlying gravitational-wave background, focusing on
transitions characterised by strong supercooling. As an application of our
analysis, we determine bounds on the parameter space of two representative
particle physics models. We also comment on the expected reach of
third-generation detectors in probing supercooled phase transitions.
