How to Enroll in Medicare
Enroll by Phone
Call 1-877-428-3929
Representatives are available 8 a.m. - 8 p.m. Eastern Time 7 days a week from October 1 through March 31. * From April 1 through September 30 our business hours are 8 a.m. - 8 p.m., Monday through Friday. TTY users: 711.
Enroll by CMS
Medicare beneficiaries may also enroll in Highmark Wholecare through the CMS Medicare Online Enrollment Center.
Visit CMS
Enroll by Mail
You have the option to enroll by mail by printing and filling out the enrollment forms.
2026 Enrollment forms
2026 Enrollment Form - PA Diamond and PA Ruby Plans
2026 Enrollment Form (Spanish) - PA Diamond and PA Ruby Plans
2027 Enrollment forms
2027 Enrollment Form - PA Diamond and PA Ruby Plans
2027 Enrollment Form (Spanish) - PA Diamond and PA Ruby Plans
Download and mail completed forms to:
Highmark Wholecare
Attention: Medicare Enrollment Department
P.O. Box 535191
Pittsburgh, PA 15253-5191
Gateway Health Plan, Inc. d/b/a Highmark Wholecare is an independent licensee of the Blue Cross Blue Shield Association. Highmark Wholecare offers HMO plans with a Medicare Contract. Enrollment in these plans depends on contract renewal.
Medicare Ombudsman Website
Best Available Evidence
Y0037_1359_M_2027
Last Updated: October 1, 2026