Per New York State rule, the Uniform Admission Deadlines for Morning Examinations is 10:00 a.m., and Afternoon Examinations is 2:00 p.m. Students arriving after those times will not be allowed to sit for the exam.
Students should arrive to school 45 minutes before their exams begin.
https://www.nysed.gov/state-assessment/regents-examination-schedules
Source: NY State Education Dept. Regents Schedules