InSan Pedro,speak with Samuel or Vincente Cumes at Casa Rosario Spanish School. They will know where you can leave the bike safely. Better yet, just around the point from the main dock ask for Maria and Joel to see if there is space to stay in one of the thier two cabins by the lake. It is across the street and down the path from the lake side Casa Rosario School. Ask Joel if he has space to lock the bike up in his shed.