By plane
From Narita Airport, the fastest and most expensive way to reach Yokosuka is to take the Narita Express to Shinagawa, and then take the Keikyu Line to the centrally-located Yokosuka-Chuo station. 2 hours; ¥3930 [¥3310 JR fare + ¥620 Keikyu fare]. With the Japan Rail Pass this trip costs only ¥620 for the Keikyu line.
Regular JR commuter trains depart Narita Airport once per hour: some trains offer one-seat rides to JR Yokosuka station, or else change at wherever the train terminates to the next train bound for Yokosuka or Kurihama About 2 3/4 hours, ¥2520. These trains offer a ¥950 Green Car seating upgrade; Green cars feature more comfortable seats and a drink and snack service.
A cheaper ride from Narita to Yokosuka is to take the Narita Sky Access train which runs into the subway. When you reach Sengakuji, change to a Keikyu Limited Express train for Yokosuka-Chuo 2 1/2 hours, ¥2020.
From Haneda Airport, take any Keikyu Line local æ®é or express æ¥è¡ train and change at Keikyu-Kamata station to a limited express ç¹æ¥/å¿«ç¹ towards Yokohama. The trip to Yokosuka-Chuo takes 50-60 minutes and costs ¥790.
By train
The fastest Keikyu trains the Limited Express "green trains" - referring to the color of the sign on the train, not of the train itself make the run to Yokosuka-Chuo 横é è³ä¸å¤® in 43 minutes from Shinagawa station ¥620. Many trains from the Toei Asakusa subway line continue on to the Keikyu Line. The ride takes about one hour from Nihombashi æ¥æ¬æ© station ¥900.
The slower JR Yokosuka Line, on the lower level of Tokyo Station, takes you to JR Yokosuka Station 75 minutes; ¥1050 which is about 2 1/2 kilometers northwest of the more centrally-located Yokosuka-Chuo Keikyu station. If you wish to use JR, be sure to take any train bound for Yokosuka or Kurihama and note that the front 4 cars of the train are removed at Zushi when Yokosuka-bound, so ask if you are not sure where to sit.
Local buses connect Yokosuka-Chuo and JR Yokosuka stations on a frequent basis ¥170.