Ferry tickets to Naoshima

Where do you buy the ferry tickets at Uno port for Naoshima?
At a office at the port or on board the ferry?
AND can you by open-ended return ferry tickets, or do we have to buy the return on Naoshima?
Checking the various timetables the trains and ferries don't seem to link up all that well, or am I missing something?
Many thanks

http://www.shikokukisen.com/en/stand/
http://www.shikokukisen.com/stand/#uno

http://www.shikokukisen.com/en/fare/

Thanks: doesn't quite answer the open ended round trip query, but it looks like we will be buying tickets on the ferry, so will ask then.

it looks like we will be buying tickets on the ferry,

From Ticket office on port before boarding.

or from the vending machine in the ticket office building (quicker if there are queues)

Thanks for replies

Sorry, pressed Reply to soon

So if we are not going on the 10am service , we buy on the ferry, correct??


Uno Port Ticket Office for Passenger Boat Services
*This office only sells tickets for the services specified below.
[For Miyanoura departing at 10:00]
[For Honmura departing at 11:55]
[For Miyanoura departing at 13:30]
During hours, the Uno ferry Service Ticket Office also sells tickets for these passenger boat services. Ticket sales begin 30 minutes before departure time.
For other boat services, tickets are sold at the boat. If you wish to take any of these boat services, come straight to the boarding pier.
* This office does not sell tickets for ferry services.

Ticket office or ticket machine in front of office.

Twp people have posted the answer, and there is also links provided to the ferry website with info also.

Thanks hakata14: guess the answers �g2 people have posted�h and the links provided which I have quoted don't correlate.
Shall go to office or vending machines as suggested.