Please click the link below!
Kyoto Sea Area Pass Official Info in PDF
If you would like to check comparison between using the pass and NOT using the pass, please check my blog page. I calculated with the fares which used before 1st April 2014 so the total fares of NOT using pass will be more than what you can see.
Anyway, there is almost no reason to don't purchase this pass for travellers.
For a day trip, absolutely buy it! (Except you are plan to stay on the beach entire your stay ;))
For more than 1 night stay travellers, to buy 2days pass or 1day pass is depends on your arrival time and your plan. Please be aware of you can buy this pass only on limited express trains from Kyoto or at train stations.