Student workers are expected to submit their timesheet for approval by their manager no later than Monday at noon following the end of each two week student pay period. 
Managers of student workers are expected to approve student timesheets by no later than Tuesday at noon following the end of each two week student pay period.
See Student Payroll Schedules for more the specific student pay period end dates.
Also, please be aware of the following:
In Workday, the Payroll team will be locking all weekly and student timesheets at noon on Tuesday in order to finish processing the payroll.  Once the timesheets are locked, users may not make any further changes and whatever has been entered into the timesheet will be paid.  Any necessary adjustments will be made to the subsequent  payroll.
In Workday, the Payroll team has visibility on the timesheets to see when time is entered but not submitted and when time is submitted but not approved.  An important new process for the Payroll team will be to monitor the timesheets after each pay period and communicate with users and managers when the timesheet process has not been completed properly.
Please submit an AskIT ticket or email with any questions.