A search for heavy long-lived multi-charged particles is performed using the ATLAS detector at the LHC. Data collected in 2012 at $$\sqrt{s}=8$$ TeV from pp collisions corresponding to an integrated luminosity of 20.3 fb $$^{-1}$$ are examined. Particles producing anomalously high ionisation, consistent with long-lived massive particles with electric charges from $$|q|=2e$$ to $$|q|=6e$$ are searched for. No signal candidate events are observed, and 95 % confidence level cross-section upper limits are interpreted as lower mass limits for a Drell–Yan production model. The mass limits range between 660 and 785 GeV.