  We study thermal freeze-out in the \textit{dark axion portal} - an axion
coupling to the dark photon and photon - considering the dark photon as the
lightest stable particle, thereby a dark matter candidate. We pay special
attention to the coscattering regime, founding viable DM scenarios fulfilling
the correct relic abundance. Furthermore, we explore the prospects of having
the axion as a long-lived particle, possibly to be observed at the LHC and
future detectors.
