After crossing I-93, Route 129 heads into Reading. The route crosses Route 28 just north of the town center before continuing eastward. At the town line with Wakefield, the route enters a rotary intersection with I-95/Route 128 at Exit 40, most of which is in the town of Wakefield. Shortly after leaving the rotary, and just after crossing the Saugus River, Route 129 turns southward along Main Street, following the eastern side of Lake Quannapowitt towards the town center. At Water Street, Route 129 turns eastward, passing the Center Depot, which is on the National Register of Historic Places and along the Haverhill Line (though currently without a stop). From Wakefield, Route 129 enters Saugus and Essex County. Passing the Breakheart Reservation, the route joins U.S. Route 1 at a cloverleaf intersection, following the route concurrently northward into Lynnfield.