Many extensions to the Standard Model predict new particles decaying into two bosons ($WW$, $WZ$, $ZZ$, $Z\gamma$) making these important signatures in the search for new physics. Searches for such diboson resonances have been performed in final states with different numbers of leptons, photons and jets, where new jet substructure techniques to disentangle the hadronic decay products in highly boosted configuration are being used. ATLAS searches for diboson resonances with LHC Run 2 data collected in 2015 and 2016 at $\sqrt{s} = 13$ TeV are summarized.