Post Offices in Waltham, Massachusetts, United States SearchSearch SearchSearch View: Grid 1View: Grid 2View: Grid 3View: Grid 4View: Grid 5View: List North Waltham Post Office No Reviews Favorite Phone: (781) 893-9520Retail Hours South Waltham Post Office No Reviews Favorite Phone: (781) 893-9841Retail Hours Waltham Post Office No Reviews Favorite Phone: (781) 893-9752Retail Hours Waltham Carrier Annex Post Office No Reviews Favorite Fax: (781) 891-5658Phone: (781) 768-4003Retail Hours Watertown Annex at Waltham Post Office No Reviews Favorite Fax: (781) 899-0626Phone: (781) 893-0694Retail Hours