IEP: If you apply for Part B during “Initial Enrollment Period or Open Enrollment Period”, you won’t have to pay a late enrollment penalty.
GEP: If you apply for Part B during the “General Enrollment Period”, the coverage will be effective July 1st. If you delay your Part B and do not have creditable health insurance coverage, you may have to pay a late enrollment penalty
SEP: If you are eligible to apply for Part B during a “Special Enrollment Period”, you can sign up during the SEP without paying a late enrollment penalty. Keep in mind that some SEPs require you to apply within 63 days of terming prior creditable health insurance coverage.