Please look at the Web-site below.
http://www.epochal.or.jp/organize/05hotel/05hotel.htm

From Narita Airport to Tsukuba Center
Long distance bus bound for Tsuchiura Station and get off at Tsukuba Center.
* Bus ticket counter is located in the arrival lobbies of Terminal 1 & Terminal 2 at Narita Airport
* Duration: about 100 min * Fare: 2,540 yen (It is subject to change.)


From Haneda Airport to Tsukuba Center
Limousine bus bound for Tsukuba Center
* Bus ticket counters are located in the arrival lobbies of Terminal 1 & Terminal 2 at Haneda Airport
* Duration: 100 -120 min * Fare: 1,800 yen (It is subject to change.)


From Tokyo Metropolitan to Tsukuba City
Tsukuba Express (Railway)
* Akihabara Station ~ Tsukuba Station
* Duration: 45 min *Fare: 1,150 yen (It is subject to change.)


High way bus bound for Tsukuba Center from Tokyo Station
* Buses leave Yaesu South Exit of Tokyo Station
* Duration: about 100 min * Fare: 1,250 yen (It is subject to change.)


From Tsukuba Center to Okura Frontier Hotel Tsukuba Epochal
5 min by taxi * 10 min (780m) by walk