Most employers have an annual open enrollment period that can fall any time during the year, but is often in the fall (for plan coverage that starts January 1st). In addition, there are special circumstances that trigger a “special enrollment period,” in which you can enroll in coverage outside the annual open enrollment period. These include loss of eligibility for coverage because of divorce or legal separation, loss of dependent status, or reduction in hours or loss of job, or certain life events such marriage or gaining a dependent through birth or adoption. Be aware, your employer may require you to enroll within 60 days of your change in circumstances. (29 C.F.R. § 2590.701-6).
On Private Health Insurance Coverage & The Health Insurance Marketplace