At this time, you are not able to defer Social Security tax. These deferrals were only allowed from September 1, 2020, through December 31, 2020. In most cases, it was not up to the employee whether to participate. Your employer decided whether they would participate in the deferral program. If your employer participated, then there was nothing that you had to do. They would simply not deduct Social Security taxes from your gross pay. If you are self-employed, then you may have decided to defer paying your employer portion of the Social Security tax. Either way, repayment of the tax was mandatory. For employees, repayment should have already taken place since it was due on January 1, 2022. For employers, half of the amount due should have been paid by January 3, 2022, while the other half must be paid by January 3, 2023.