Route 25 begins at a trumpet interchange with I-495 and I-195 in Wareham, Massachusetts; the two left lanes of Route 25 west mainline onto I-495 north, with the right-hand lane serving I-195 via Exit 1. From I-195, Route 25 east is accessible via Exit 22A; I-195 terminates at the interchange. Interstate 495 also terminates at its junction with Route 25; the two southbound lanes of I-495 default onto Route 25 east. After the interchange with I-195 and I-495, Route 25 begins to head in a southeastern direction into the town of Wareham as a six-lane freeway. The route passes under Tihonet Road and through Maple Swamp, located at the northern end of Parker Mills Pond.