The Gellert is ok but overpriced. A better alternative is the Shechenny, which is at the end of one of the Metro lines, the yellow one I think. The building is magnificent, set in a park, the three pools are good and the thermal institute attached to it and included in the entry price is wonderful.

On a fine day it is a suntrap and people sit around in the pools playing chess on floating cork boards. The bar/restaurant is excellent and well priced with a marvellous sun lounge. We found the Gellert cold and expensive by comparison. On your way back into town divert to the bar and restaurant at the entrance to the park, the wooden bar is a work of art.

The update is inaccurate. It is Szėchenyi, not Shechenny which looks ridiculous in Hungarian. It is indeed on the yellow (No 1) metro line but not at the end! Get off at the Szėchenyi gyógyfürdő, otherwise you will end up in Mexikói út which is not recommended. The Szėchenyi is very atmospheric but it should be pointed out that these days, apart from the old guys playing chess, the place is packed out with Russian mafia and their tarts. The entry price is NOT wonderful - go to Csillaghegy Strand (lido) nestling on the side of a leafy hill (take the HÉV train towards Szentendre) for a much more authentic and reasonably-priced Magyar experience. The Gellért spa has a lot of history, however families might like to know that the outdoor sunbathing area is a popular gay pick-up zone, where young Romanian rent boys ply their trade. Budapest is the porn capital of Europe so be warned.