Yes, as long as you do so during the Open Enrollment period.

If you are under age 65 and enrolled in employer-provided retiree health coverage, and if your income is at least 100% of the Federal Poverty Level ($15,060 for a single adult or $20,440 for a family of two) in 2025, you may also qualify for premium tax credits. However, there’s one exception. Some employers may provide retired employees with access to a health reimbursement arrangement (or HRA) that the retiree may use to reimburse medical expenses, including an individual plan through a health insurance Marketplace. A retiree who signs up for an HRA offered by a former employer is considered to have minimum essential coverage from an employer and would therefore not be eligible to claim a premium tax credit if he or she enrolled in a Marketplace plan.

Remember that outside of Open Enrollment, you cannot voluntarily drop your retiree coverage and replace it with Marketplace coverage.