The system for long-distance ferry bookings in Japan is a little peculiar. Tickets go on sale from 9am two months in advance of the departure date, e.g. tickets for departures on the 12 October will go on sale at 9am on 12 August. This means that if you want to secure a ticket at this time you will need to book the return leg of the journey separately.
The system also means that securing a space on the more popular routes during the peak holiday seasons (e.g. obon) is close to impossible. Tickets become available at 9am and sell out within a matter of minutes. The best option is to hedge your bets and try a few alternative routes, even if it means traveling further to a different ferry terminal. Then you have to worry about the return leg.
Fortunately given all this uncertainty cancellation policies are flexible. Passengers are able to cancel their tickets up until one week before departure for a fee of just 200 yen, and up to two days before departure for 10% of the fare (these terms are generally standard among the inter-regional ferry companies).
Like with an airline, passengers need to check-in prior to departure at the terminal office. Here you will be issued with ticket (you may need to pay again if it’s lost so be sure to keep it safe!) and a ticket for your vehicle if applicable.
The ferries are typically capable of holding 700-800 passengers, and offer various amenities while on board including a restaurant, small bar, lounge area, and gift shop among other things. Vending machines sell drinks (including alcoholic beverages) and snacks, but many passengers bring their own food and drink on to the ferry.
For those boarding with a vehicle, it’s advisable to have valuables and other items you wish to take on board in a small separate bag because one the ferry departs the port the lower deck with the trucks and passenger vehicles are out of bounds until arrival.