Plymouth is about 40 miles south of Boston, roughly an hour by car or commuter rail.
By train, the MBTA Plymouth/Kingston Commuter Rail line runs from South Station in Boston to Plymouth station, with trains running several times daily. The journey takes around 75 minutes and costs a few dollars on the commuter fare. Plymouth station is about a mile from the waterfront — a short taxi or rideshare ride.
By car, take Route 3 south from Boston (or I-93 south to Route 3). The drive is straightforward outside of rush hour. Parking in the downtown area is paid; the large lots near the waterfront fill early in summer.
There is no direct service from Logan Airport — take the Silver Line or the Blue Line to South Station and board the commuter rail from there.