Saint Martin’s island is the largest  offshore  island of Bangladesh which is one of the most beautiful tourist spots in the  world.  But  as  the  island  is  far  away  from  the  mainland,it   is   not   connected   to   the   main   grid   of   the   country.   This paper  proposes  an  optimized  stand-alone  green  hybrid  system to supply electricity for the inhabitants & tourists of the island.Considering  1000  households  for  all  of  its  inhabitants  and  200 hotel   rooms   for   tourists,   the   average   daily   load   is   1135.82kWh/day  with  an  annual  peak  load  of  227.76  kW.  The  aim  of this  paper  is  to  design  the  most  cost  efficient  optimized  stand-alone  green  hybrid  system  which  provides  zero  emission  and 100% renewable fraction. HOMER(Hybrid Optimization Model for  Multiple  Energy  Resources)  is  used  to  design  this  system.The  simulation  results  show  that  a  hybrid  system  with  659  kWPV array, 3073 strings of batteries, 245 kW converter forms the most  optimized  stand-alone  system  with  COE(Cost  of  Energy)of $0.266 and NPC(Net Present Cost) of $1379832. Significantly,energy cost of the proposed system is viable in context with socio-economic condition of the country which will eventually provide the  power  solution  maintaining  the  scenic  beauty  of  the  island.