Swimming pool near Dongsi intersection, Dongcheng District, Beijing
It's the one I go to every day, Dongsishitiao Haosha Fitness Club, which seems to be 1399. It has a swimming pool, fitness classes and sports equipment. There is a Julong Garden Building with basement on the west gate road of Dongsishitiao Workers Stadium. I think it's ok. The price is quite low. I usually swim in class.