The closest airport is Girona, about 35km away.
The largest airport in the region is Barcelona, about 100km away.

If you rent a car, you drive to either St. Feliu,
and then you have only 3km to the north, till S'Agaro; 
or you can drive to Platja D'Aro, 
and then you have only 3km to the south, till S'Agaro.

If you plan to take public transportation,
busses in Spain are relly unexpensive.
For about E15 one way you can ride from Barcelona to St. Feliu,
and for about E5 one way you can ride from Girona to St. Feliu.

From St. Feliu or from Platja D'Aro,
you can take taxi,
or you can even walk, 
if you do not have too much luggage.

The walks to S'Agaro
(either from St. Feliu or from Platja D'Aro), are the following:

a. By big road, which cuts thru the penninsula, 
   15 minutes on foot.
b. By small road, which is paved and goes by the sea, around the penninsula, 
   30 minutes on foot.
c. By fantastic coastline path, 
   1.5h on foot.

Please, see the enclosed map on the conference web site, for details.

Once you arrive to S'Agaro coast line (the beach is called St. Pol),
you can see hotel HOSTAL DE LA GAVINA from each corner of the beach!