Bled Island stands in the lake and looks stunning and enticing from the shore. There are several ways to get here. Firstly you could rent a rowing boat and row here but you need to be fit as it's a lot further than it looks. Secondly you could swim--now you really need to be fit for this option and you can't go in the church once here unless you manage to bring some clothes with you. So really the only sensible option is to pay a small fortune to the pletna (flat gondola) and be taken there. It cost 1800 SIT for the ride to the island and back, but it has to be done. Once on the island you have 30 minutes before the pletna leaves again, and this gives you just enough time to visit the Church of the Assumption, a pretty place inside and out. Then there is the Chaplain and Provost houses and the wishing bell. You make a wish and ring the bell which bascially everyone does. Then you just have time to buy an icecream or trinket, back around the island on the tiny path around the edge and back onto your pletna.
A visit to the island isn't essential, but it is fun.