You can beat the islands, but there are always more islands to be made.
You cannot actually "win" Poptropica. The islands are designed for education and amusement, and the games will be easier for older or more experienced players. It is not a competition, because all the players are anonymous. This also means that one player may have more than one account, although credits cannot be added or transferred from one username to another.
(For solutions to all of the islands, see the related question.)
you win
You win a medallion on every island and also you get 100 poptropica dollars at the store. This goes for every island.
Kinda of you get 100 poptropica credits to use in their store
to win poptropica
get the bingo troll
try harder
you have to try to get it on the orange thing to win
You halft to win every game on the wimpy boardwalk
You get the Island Medallion from Early Poptropica and Shark Tooth Island. (note : this is from 2007 when Poptropica first came out!)
nothing:( :( :( :( :( :( :( look sideways
You win a spud gun.
you need to win it