  We study the supersymmetric version of the type-II seesaw mechanism assuming
minimal supergravity boundary conditions. We calculate branching ratios for
lepton flavour violating (LFV) scalar tau decays, potentially observable at the
LHC, as well as LFV decays at low energy, such as $l_i \to l_j + \gamma$ and
compare their sensitivity to the unknown seesaw parameters. In the minimal case
of only one triplet coupling to the standard model lepton doublets, ratios of
LFV branching ratios can be related unambigously to neutrino oscillation
parameters. We also discuss how measurements of soft SUSY breaking parameters
at the LHC can be used to indirectly extract information of the seesaw scale.
