  In supersymmetric models with explicit breaking of R-parity the lightest
supersymmetric particle (LSP) may be the lightest stau, $\stau_1$. Such a
scenario would provide a clear sign of R-parity violating SUSY, although its
phenomenology may resemble that of a charged Higgs boson, $H^\pm$. We discuss
various ways of distinguishing a LSP $\stau_1$ from $H^\pm$ at future
colliders, and address the case of $\stau_1$ mimicking the signal for $H^\pm$.
As an example we suggest that the recent L3 signal for $H^+H^-\to qq'qq'$ and
$H^+H^-\to qq'\tau\nu_{\tau}$ could be more easily explained by a LSP
$\stau_1$.
