By train: Greater Anglia runs direct trains from London Liverpool Street to Harwich International, with a change at Manningtree. The journey takes around 1 hour 45 minutes. Harwich International station sits directly next to the ferry terminal, so if you are catching the boat to Holland you walk off the train and onto the quay.
By ferry: Stena Line operates the Harwich–Hook of Holland route, with both day and overnight crossings. The crossing takes around 6.5 hours. Stena also offers a Dutchflyer Rail & Sail ticket that combines a Greater Anglia train from any station on the network with the ferry crossing, which is good value if you are not bringing a car. There are typically four sailings per day in each direction.
By car: Harwich is at the end of the A120 from Colchester, which connects to the A12 and the wider motorway network. From London allow around 90 minutes in normal traffic. Parking is available at the ferry terminal.