One is the Aqua speaker from NYNE. The Aqua has an IPX7 rating, which means it can be fully submerged for up to 30 minutes in about 3 feet of water. It's designed to float on the surface of a pool or lake while pumping out music from a mobile phone or other Bluetooth device.
It also has a microphone, making it useful as a speaker phone, perhaps for conference calls in a hot tub. The Aqua has a list price of about $130.
You can replace the tail with a suction cup an stick the speaker on a window.It also can be immersed in three feet of water for up to 20 minutes.
The Swimmer sells for about $60 at Boom's website.