Open Enrollment Period
The Open Enrollment Period (OEP) starts on November 1st prior to the start of a plan year (PY) and ends on January 15th of that PY. During this time period, people can apply for a new health plan for the upcoming year. If you enroll in a plan by December 31st during OEP, it will go into effect on January 1st of the new year. If you enroll in a plan between January 1st and January 15th of OEP, it will go into effect on February 1st of that plan year.
Special Enrollment Period
The Special Enrollment Period (SEP) is year long and can occur even during the Open Enrollment Period - if you qualify. You're eligible for the Special Enrollment Period if you have certain qualifying life events, like getting married, having a baby, or losing other health coverage. If you qualify for an SEP, you usually have up to 60 days following the event to enroll in a plan.