Doubly charged scalars are part of the spectrum of various Beyond-the-Standard-Model scenarios, from mechanisms for the generation of the neutrino masses to the Left-Right models. Direct searches in the pair production channel have been performed at the LHC, setting bounds on the mass of the particle. Future linear colliders will have a great potential to test the direct production of this particle as well as its couplings to the charged leptons. Moreover, as this particle allows for lepton flavour violation, complementary bounds are also provided by low energy measurements.