Traveling from Saitama to Karuizawa is primarily serviced by the Nagano Shinkansen, specifically the Asama and the Kagayaki trains. The Kagayaki train is the faster option, reaching speeds of up to 260 km/h (162 mph) and covering the distance in approximately 1 hour and 15 minutes. This service offers fewer stops, making it ideal for those looking to reach their destination quickly. On the other hand, the Asama train, while also providing a comfortable experience, takes about 1 hour and 50 minutes as it makes additional stops, catering to those interested in exploring intermediate towns along the way.
Both trains feature different classes of seating with Ordinary and Green cars available. The Green car offers more spacious seating and additional amenities for a more relaxed journey. Onboard services include wifi, food and beverage options, and clean restroom facilities, ensuring a pleasant travel experience. For travelers aiming for speed and efficiency, the Kagayaki is the recommended choice, whereas the Asama is better suited for those who prefer a slightly longer journey with more local stops.