Please check the expiration date of your passport before making your travel plan.
Tsukuba (or ``Tsukuba Science City'') is located about 60km north of Tokyo and about 40km northwest of the Narita International Airport. Tsukuba Center and OKURA Frontier Hotel TSUKUBA, within a walking distance each other, are in the central area of Tsukuba and about 10km south of KEK.
The easiest way is to take a direct bus service, called Airport Liner ``NATT'S'', from the Narita Airport through Tsukuba Center to Tsuchiura Station. Tickets are available at the ``Airport Limousine Keisei'' counter on the 1st floor in the arrival lobby, and the fare is 2,540 yen per person. (Note that the ``Airport Limousine Bus'' counter on the same floor, operated by another company, does not take care of the NATT'S bus service.) The bus stop is located right outside of the terminal, and the bus leaves the Airport at 07:20, 09:05, 10:35, 12:50, 14:30, 16:15, 17:20, 18:45, and 20:10.
It takes about one hour and 40 minutes to Tsukuba Center. (The bus, without going through Japanese Expressways, is hardly caught in a traffic jam and thereby the schedule would be reliable.) There are six bus stops: ``Shin-Tone-Machi'', ``Ryu-Ga-Saki New Town'', ``Ushiku'', ``Hitachino-Ushiku Station'' (some of these are skipped occasionally), ``Tsukuba Center'' and ``Tsuchiura Station''; you should ride off the bus at Tsukuba Center (not Tsuchiura Station).
In case your flight does not match the bus schedule (leaving the Airport at 20:10 in the last), then you must go the Tokyo area at first by the JR line, Keisei line or Airport Limousine Bus (about two hours, 2,000-3,000 yen). The transportation from Narita to Tsukuba by taxi will cost as much as 20,000 yen.
Take the JR Yamanote line to the Akihabara terminal and find out a sign "TX" for Tsukuba Express railroad, which is located deep underground at the east side of the Akihabara station. It takes about 10 miniutes from JR to TX on foot.
At the TX Akihabara station, buy a ticket to Tsukuba station (1,150 yen per person) and take a Rapid train (45 minutes) or a Semi-Rapid train (52 minutes); a limited number of Local trains reach the Tsukuba station (57 minutes). Take the exit A4 or A3 of the Tsukuba station to the Tsukuba Center bus terminal (and OKURA Frontier Hotel TSUKUBA).
TX trains leave the stations every $\sim$ 15 minutes; the first and last trains leave the TX Akihabara station for the Tsukuba station at 05:30AM and 23:30, respectively, and the first and last trains leave Tsukuba for Akihabara at 05:07AM and 23:14, respectively. You can enjoy a short trip from Tsukuba to Tokyo easily by using the TX trains.
If you are going to visit KEK directly via Tsukuba Center by a TX train and a public bus service, the information on their connection is available from our Web page
The easiest way to returning to the Narita Airport from Tsukuba is again to take the direct bus service, leaving Tsukuba Center at 06:20, 07:20, 08:50, 10:20, 11:55, 13:25, 14:35, 15:50, and 17:35. The ticket going to the airport, however, needed to be reserved and purchased at least one day in advance. The ticket can be purchased not only at Tsukuba Center Bus Terminal but also at KEK Grocery.