Using the data collected by the ANTARES neutrino telescope from 2009 to 2016, the optical
module (OM) efficiencies have been determined through the so called K40 method. The results
have been computed on a 6-day basis, after applying selection cuts in order to provide reliable
time-dependent OM efficiencies for most of the individual OMs. The results show an impressive
stability over time, as well as the benefit of the high voltage tuning (HVT), which is a dedicated
procedure aimed to keep efficiencies at their best.