When Is Medicare General Enrollment Period? 
The general enrollment period for Medicare is January 1 - March 31 of each year . The effective date for your Medicare coverage will be July 1 of that year . When you enroll in Medicare Part B , you activate a 6-month window -LRB- your initial open enrollment period -RRB- to purchase any Medigap plan with no medical underwriting . A Medigap plan helps you create a very predictable cost structure for your healthcare expenses . Please note , depending on how long it 's been since you were first eligible for Medicare , you may be subject to a late enrollment penalty for your Part A and/or Part B coverage . if you 're coming off of group health insurance through your employer , you would be eligible for a special enrollment period and get coverage starting the first of the following month you applied and you would not be subject to a late enrollment penalty . I hope the information is helpful - please feel free to contact me for help and if you have any other questions . Thanks very much . 