The following is when you need to file your final return:
When To File
Generally, an S corporation must file Form 1120-S by the 15th day of the 3rd month after the end of its tax year. For calendar year corporations, the due date is March 17, 2025 (March 15th falls on Saturday). A corporation that has dissolved must generally file by the 15th day of the 3rd month after the date it dissolved.
See https://www.irs.gov/instructions/i1120s#en_US_2024_publink11515kd0e416
