Himiko waterbus question

I saw from the their website that Himiko waterbus runs from Toyosu to Asakusa but I'm not sure because I don't understand Japanese at all. I want to confirm if this is true and where can you book the tickets online? I believe that it will be crowded and I really want to ride the waterbus. If tickets are not available on the internet, how many minutes earlier must I arrive at Toyosu in order to book 7 tickets? Thank you!

I want to confirm if this is true and where can you book the tickets online?

Unless you are a group of 15 or more people, I believe the only way to purchase the ticket is at the ticket counter in person on the day of travel.

how many minutes earlier must I arrive at Toyosu in order to book 7 tickets?

The tickets go on sale at 10:30. I am not sure how popular these cruises are, but theoretically they could sell out at any time of the day. If they do not sell out - and I have the feeling that is the case on most days - then you should be able to purchase tickets just until shortly before departure time. I recommend to arrive at least 15 minutes before departure time.

Thanks! How many people can fit in one waterbus?

I've taken the Himiko twice before. Both times from Asakusa to Odaiba. You have to go down before the scheduled time to buy the tickets. Both times that i've taken it, its relatively almost full but there's still a lot of space for you to walk around. There are limited seats so it's first come first serve. But not to worry about overcrowding or no seats left, i'm sure you can get to ride the Himiko as long as you go down at least an hour in advance to get your tickets. http://www.suijobus.co.jp/ship/himiko.html