If you are looking for the Matagorda Medical Group Patient Portal, click here. CONTACT US. Matagorda Regional Medical Center. 979.245.6383 104 Seventh Street Bay City, Texas 77414. Visitor Hours. Mon - Friday: 8 am - 7 pm Saturdays: 8 am - 6 pm. MRMC Foundation Hours. Mon - Thur 8 am - 6 pm. QUICK LINKS..