Can I enroll in a Medicare Advantage plan from January 1 - March 31?

Yes. January 1 - March 31st is Medicare's Open Enrollment for Medicare Advantage plans only. During this time frame if you currently have a Medicare Advantage plan you can change to another Medicare Advantage plan once. The effective date will be the month following your new enrollment. (2024). Medicare & You (2024th ed., p. 72). CMS