Delta Spa Hamam
Delta Spa Hamam sits inside the Delta Hotels by Marriott Istanbul Haliç in Kağıthane, so it is a separate trip from the Laleli–Sultanahmet old-city cluster rather than a stop on it. It is open every day from 12:00 to 22:00 and combines a Turkish bath with a pool, steam room, sauna and massage. Google shows 4.9 from 848 reviews, but prices, session lengths and women/men arrangements are not published.