Rehoboth Beach is about two hours from Washington DC, two and a half hours from Philadelphia, and three hours from Baltimore, making it accessible for a weekend trip from any of the major mid-Atlantic cities.
By car, the most direct route from Washington is the Bay Bridge across the Chesapeake, then Route 50 east across the Delmarva Peninsula. Traffic on this route is severe on Friday evenings in summer and Sunday afternoons returning; leaving DC before noon on Friday or after 7pm avoids the worst of it.
There is no direct rail service to Rehoboth Beach. Greyhound and other bus services run from Washington and Philadelphia to Rehoboth, though the schedules are not always convenient. The DART First State bus service connects Lewes and Rehoboth to the Amtrak station in Wilmington, which has regular service to New York and Washington.
Many visitors arrive via the Cape May-Lewes Ferry from New Jersey, which docks at Lewes, fifteen minutes north of Rehoboth. This is a scenic and practical option for those coming from the north.