Hi,
We did that trip in September last year. The only difference was that we flew into Ljubjlana instead of Trieste, hired a car and drove down to Portoroz. There was a considerable saving flying Easyjet compared to Ryanair into Trieste on this occasion, it might have had something to do with the bank holiday dates we went over.
Portoroz is stuck in time warp but is still an enjoyable destination. It is like a 1970/80's destination trying to catch up, no surprise with Slovenia being part of the former Yugoslavia.
I am doing it a dis-service really. If you want sun, sea, bars and reasonable restaurants it is perfect. If you want sand, you'll be disappointed, it is like concrete central and many of the beaches are concrete(!) or grass and privately owned by the hotels.
Temps were 30c most days in September, so June should be pretty nice as well.
We stayed in the Hotel Rosa, part of the Metropol group. It is a nice hotel, brilliant location with average rooms, mega views of the sea. Rates were reasonable, although it tended to be heavily populated with germans, no problems with that but you know the stories about bagging the sun beds in the morning.....The hotel shares facilities with the other on-site hotels, although the olympic sized pool was never that busy in September (I don't know why). The hotel rate included breakfast which was very nice.
There are plenty of bars in Portoroz although not as many as I thought there would be. All are pretty much of a muchness to be honest. The same could be said for the restaurants although the mexican just down from the Metropol is absolutely the tops!!!! Well worth a visit.
Piran will be worth a visit and is only 10mins from Portoroz, you can get a boat transfer there and is reasonably cheap. Lovely, quaint and a nice contrast to Portoroz.
Not sure on internet links in hotels, not in the Rosa I think. Maybe in the 5star Grand Hotel Metropol????
Let me know if you need further info. We were there for a week and managed to fill our time easily.
Julian