Downtown Portsmouth is compact and best explored on foot. The walk from the waterfront and Prescott Park north to the historic district and Market Square takes about fifteen minutes, and most of the city's attractions fall within this corridor. Comfortable walking shoes are adequate; the streets are flat and well-maintained.
For exploring further afield — the USS Albacore (about a mile north of the centre), or the Great Bay estuary — a car or bicycle is useful. Bike rentals are available from local shops. The city has a limited bus network through COAST (Cooperative Alliance for Seacoast Transportation) but the schedules are not designed for tourist use.
Rideshare services operate throughout Portsmouth and are the practical option for reaching the waterfront ferry terminal or the airport when you don't have a car.