Hartlepool sits on the Durham Coast Line, the railway that runs between Newcastle (35 min) and Middlesbrough (15 min). The station is a five-minute walk from the marina and the museums. From further afield, change at either of those cities.
By road, the town is reached from the A19, the main artery up the east of England — it's about 90 minutes from Leeds, two hours from York or Manchester. Parking around the marina is plentiful and cheap.
The nearest airports are Newcastle (40 min by car) and Teesside International (25 min); both are small but useful for domestic flights.