We stayed at the sister hotel Sirmione but were allowed to use the SPA in this hotel since ours was being refurbished. For sure this is a nice hotel, cars in the car park went from Audi/BMW upto Ferraris. Location wise its just before you get to the pedestrian area in Sirmione on the right hand side. All I can comment on is the SPA since we didnt stay in a room there, it was very nice.

On entering we were shown to a kind of shared changing room with just 4 lockers, all very up market, Slippers were provided along with towels all rolled up. Access to the SPA is down some spiral stairs, nothing much is signposted. The SPA is a proper thermal one (very warm and a smell of Sulphur). Swimming hats must be warn but they are in a basket as you come down the stairs. The outdoor pool and area is very nice, in November only a couple of people around but I guess in Summer it must get busy judging by the number of sun loungers.
Tea/Juice/Water are provided inside as well as a Sauna and Gym. There are lots of treatment rooms inside although we didnt have any treatments (they looked pretty expensive),

Overall the Hotel Spa was very good, would like to go back - we went up to the public Spa at the North end of Sirmione and it was very busy, the hotel spa on the other hand was empty.

We stayed here for three nights in September (10th, 11th, 12th) and will not be going back. The 5* rating is not even comparable to a 4* hotel we are now in 30km up the coast in Salo. The staff were not friendly, indeed we often felt unwelcome. You can not deny the great location, but at £300 a night, the view is expensive! We ate out in the town every night as Sirmione offers a great selection of restaurants with far more atmosphere than Grand Hotel Terme. Breakfast was adequate, but asking for anything not on the buffet was refused. Slightly surpising as all other hotels in Italy we have stayed in have been happy to oblige. We visited only just after peak season and the hotel was clearly running down for the autumn season (one wine bar and restaurant closed). However, they continued to advertise the two restaurants and bars in the rooms and on the website. This was misleading and rather frustrating.

I cannot speak for the hotel, but the spa is overpriced with very little to offer. The water smells bad, the locker room procedure is absurdly complicated, and there are a couple of jacuzzis, one hot/cold pool, and that's it. The only nice thing is the view of the lake, but that can be seen from elsewhere. For a relaxing spa experience, this is not the place.

We stayed at the Hotel Terme as part of our holiday in Italy. The location is great, on the lake shore and very near to the old town of Sirmione, which has much charm, unfortunately the same cannot be said for the the Hotel generally and staff in particular. The hotel has a sterile feel to it, with very little ambience and despite the hotel being full the communal areas were very quiet. The thermal area consists of a lukewarm, pool of green water, which was not particularly thermal, clean or health inspiring. The staff made no effort to speak when we entered the spa area and although we had treatments, it was as though they were the ones doing you a favour by agreeing to these. In the evening the restaurant was deserted, so we ate in Sirmione. On our return, the air conditioning did not work and made a noise like an old diesel engine and by midnight, despite calling reception the temperature in the room was more than 26 degrees. At 1am the night porter agreed that the A/C was indeed broken and moved us to a "classic" room which was tiny and best described as a "Formica" room. In the morning I suggested that this was not what I had paid €350 for and was told that the original room with the broken A/C was in fact an upgrade (which they failed to inform us of at check in) and that the €350 was for the room we had to move to at 1am, therefore the hotel had really done us a favour by allowing us to stay in the hot room by the elevator, with the broken toilet in the first place and that this room should have been €400 - At no point did the staff apologise for any inconvenience or regret that the room had broken facilities. €400 for the above - you decide...but we decided to check out - early!