  We consider the charged scalar boson phenomenology in the simplest effective
low-energy R-parity breaking model characterized by a bilinear violation of
R-parity in the superpotential. This induces a mixing between staus and the
charged Higgs boson. We show that the charged Higgs boson mass can be lower
than expected in the MSSM, even before including radiative corrections. We also
study the charged scalar boson decay branching ratios and show that the
R-parity violating decay rates can be comparable or even bigger than the
R-parity conserving ones. Moreover, if the stau is the LSP it will have only
decays into standard model fermions. These features could have important
implications for charged supersymmetric scalar boson searches at future
accelerators.
