The list of hotels and a dormitory is presented at the URL;
https://wao2023.kek.jp/accommodation/index.htm
Hotels are available near Tsukuba station, 10-minute walk from the venue, and the next station Kenkyu-Gakuen station, 3-minute ride on train.
(Unfortunately, the hotel besides the venue, JAL city, is still allocated for Coronavirus infection Sanatorium.)
As of August 6th, hotel availability began to be tight. It seems that every internet service provides different result. And the hotel itself tends to answer that the rooms are not available. Please research several internet services to find a room. (Japanese internet travel services often provide more rooms. If you cannot find a room, please contact us.)
Hotels may provide 10% discount for KEK visitors, however, Internet services for hotel reservations provide more reasonable offers as those hotels recommend. (The WAO2023 office already released all rooms because of that.)
While each of those hotels accommodates 100 - 250 guests, prices may change. Normally, earlier is better.
Dormitory is available at KEK, and the bus services between Tsukuba station and KEK are provided twice an hour and take approx. 25 minutes. The timetable is at the URL;
