Updated for 2016. All images from the official Hilton Odawara Site.
The Hilton Odawara in Kanagawa are once again this year, very kindly, offering a photo with Santa opportunity daily until the 25th. This event is already running, since November 4th. Each day between 3 pm and 4 pm you can meet Santa in the front lobby of the Hilton and request to get your photo taken with him. This is a free event and they welcome people of all ages.
The front lobby also has a spectacular Christmas train and a Christmas Market. Their full Christmas programme can be viewed here:
Information on the Hilton hotels in Japan in English here: http://www3.hilton.com/en/hotels/japan/hilton-odawara-resort-and-spa-TYOODHI/index.html
From their English site:
DIRECTIONS BY CAR FROM THE HOTEL STAFF
Take the Metropolitan Expressway (Kuko chuou) to the Tomei Expressway Atsugi Interchange. Take Odawara Atsugi Road to the Ishibashi Interchange onto Route 135, then the intersection at Manazuru Road to the Hilton Odawara Resort & Spa.
DIRECTIONS BY TRAIN
Take the Tokyo Monorail to Hamamatsucho, then the JR Yamanote Line to Shinagawa. Take the bullet train to Odawara then free shuttle bus (Mon to Fri, except holidays) to the hotel. Free shuttle is available also from Nebukawa Station daily.