Getting to the Island is usually made by plane, flying from far, but those coming from Spain have alternatives to plane, either from Barcelona or Valencia.
It takes half a day each way, and may be boring. In our first visit we went in a overnight trip, and sleeping in a bouncing boat was almost impossible. The return was during the day, and then it was boring, boring, even disguised by the boring table games.
No! Flying is the best option, and low-cost reinforces it. Unless you want to take the car with you...