No, Disney does not run a bus to SeaWorld from WDW. But, at the TTC you can catch a Lnyx bus. This is Orlando's transit system. You can get a schedule at the TTC. It runs every 30 minutes, maybe at 10 past the hour and then at 20 to the hour or some such thing. It costs about $1.25-1.50 pp each way. Be sure to have exact change. When you get on the bus, tell the driver that you are going to SeaWorld. You get dropped at at the entrance to the parking lot. Cross the parking lot and you're there. For the return, you cross back over the lot, cross the street and look for the bus stop sign with the 'paw print' on it...this is Lnyx's symbol. It should be right across from where you got off the bus. It takes about 30 minutes. Very easy.