See BITSAT will be held from May 16 to 31. This means that it will be available on all days and not a specific day for any centre. You will have to book the BITSAT exam slot between March 23 to April 5 where you should choose the date, timing and the centre if there are more than one like Mumbai. Then the hall ticket will be generated. So the date and time will be as per your convenience if you book as soon as it starts.