The Gellert Baths are open everyday from 6am to 8pm, every day of the week.
You'll be delighted to know that they're also open almost 365 days of the year (excluding days when they are closed for maintenance work etc). The Gellert Baths are even open on public holidays such as Christmas Eve, New Year and Easter; so regardless of when you visit Budapest, you're likely to be able to experience the incredible Gellert Baths facilities and services!