There are various places where you can swimm in jogja. but these are my favorite places: hotel Melia Purosani, Hotel Sheraton, Hotel Hyatt (it has sliding board). If you don't stay in these hotel, you still can use this facility, but you have to pay more. The last time I went to Hotel Hyatt, swimming for local people cost Rp 40.000, for foreirgner Rp 100.000. And you'll get a drink & a towell. I heard, for the same price, in Melia Purosani, you can use the sauna. But my best place still: Tirta Sani. It's a beaten path. It lays within a complex hausing, Tirta Sani. You can reach it from Jl. Kyai Mojo (Mirota Jl. Godean) or Jl. Jambon in Jl. Magelang. It cost Tp 20.000 and you can use the fitness facility. The scenery is so beautifull, but the bathroom sometime not so comfortable. If you like to jump, the best place to do it is at ikip pool, near UNY kampus.