🌸 Basic Information / Overview
Line Name: Keio New Line (京王新線)
Operator: Keio Corporation
Route Length: Approx. 3.6km / Number of Stations: 4 (Shinsen-Shinjuku・Hatsudai・Hatagaya・Sasazuka)
Opening Year: 1978 (Shinjuku〜Sasazuka)
Connecting Lines: Shinsen-Shinjuku (Toei Shinjuku Line) / Sasazuka (Keio Main Line)
Main Feature: A connecting line between the Toei Shinjuku Line and Keio Line / Part of a four-track structure
📜 History & Background
Opened in 1978 to ease congestion at Keio Line’s Shinjuku Station and to enable through service with the Toei Shinjuku Line.
The underground platform at Shinsen-Shinjuku Station serves as the starting point for direct operations with Toei Shinjuku Line trains.
Today, it provides seamless access from Shinjuku to the eastern part of Tokyo — including Ichigaya, Kudanshita, Jimbocho, and Motoyawata.
🚆 Operational Features
・Through Service: Fully connected with the Toei Shinjuku Line (Keio→Toei→Motoyawata, etc.)
・Train Types: Express / Local (Limited Express trains on the Keio Main Line do not run here)
・Platform Layout: Underground platform at Shinjuku, located separately from JR and Keio Main Line ground platforms
・Junction: Merges with the Keio Main Line at Sasazuka / Connects Shinjuku area with Motoyawata-bound trains
🌟 Highlights (Advantages)
✅ 1. Excellent Direct Connection with Toei Shinjuku Line
Direct access to key business districts such as Motoyawata・Ichigaya・Kudanshita・Jimbocho without transfers.
Perfect for commuters heading to Chiyoda-ku and Chuo-ku areas.
✅ 2. Avoids Shinjuku Station Congestion
Unlike the crowded ground-level Keio Line platforms, the underground Keio New Line offers smoother passenger flow.
✅ 3. Fast with Express Service
Not only local but also express trains run / Approx. 6 minutes from Shinsen-Shinjuku to Sasazuka.
Easy transfer to Keio Main Line for destinations like Chofu and Hashimoto.
✅ 4. Great Balance of Residential & Urban Convenience
Hatsudai・Hatagaya・Sasazuka are popular neighborhoods for their balance of livability and accessibility — ideal for both singles and families.
⚠️ Points to Consider (Disadvantages)
❌ 1. Relatively Low Recognition
Some people think it’s “separate from the Keio Line,” so awareness of the Keio New Line itself is low.
In practice, it’s often perceived as an extension of the Toei Shinjuku Line.
❌ 2. Distance from Keio & JR Shinjuku Stations
The underground platform (Keio New Line) is separate from the ground-level Keio Main Line station.
It’s also a bit of a walk from JR Shinjuku Station, making transfers slightly confusing for first-time users.
❌ 3. Limited Train Types
Limited Express and Semi Express trains do not operate via the Keio New Line — only local and express types.
🧺 Living Convenience (Livability)
CategoryRatingComment
Transportation★★★★★Direct to both east & west Tokyo / Express available
Shopping★★★★☆Sasazuka & Hatsudai have shopping streets and station buildings
Environment★★★☆☆Quiet residential area but few parks
Education & Healthcare★★★★☆Located in Shinjuku & Shibuya wards / good facilities
Safety★★★★☆Calm residential atmosphere / Hatagaya & Hatsudai are especially safe
🏠 Real Estate Information
💴 Average Rent (as of 2025)
Station1R・1KFamily (2LDK〜)Comment
Hatsudai¥90,000〜¥110,000¥170,000〜¥220,000Near Tokyo Opera City / Excellent city access
Hatagaya¥80,000〜¥100,000¥150,000〜¥200,000Balanced area with shopping & housing
Sasazuka¥85,000〜¥110,000¥160,000〜¥220,000Close to Shinjuku / Convenient connection to Keio Main Line
🏘 Housing Trends
The line offers a variety of housing — from single-person apartments to low-rise family homes.
Hatagaya & Sasazuka are especially popular among younger couples and dual-income families.
Newer properties are higher in rent, while older ones offer better cost performance.
🎯 Recommended For
✅ Commuters/students who want to minimize transfers in central Tokyo
✅ Those who work or study along the Toei Shinjuku Line (Ichigaya・Jimbocho・Motoyawata)
✅ People seeking good balance of city convenience & residential comfort (Hatsudai・Hatagaya・Sasazuka)
✅ Those who prefer calmer stations to busy JR Shinjuku
📌 Summary
The Keio New Line is a short but highly convenient route designed for direct connection with the Toei Shinjuku Line.
It links “Toei Shinjuku Line area × Shinjuku × Keio Line” in one seamless route — making it ideal for commuting and daily travel to Tokyo’s east side.
Neighborhoods like Hatsudai・Hatagaya・Sasazuka offer a comfortable balance of quiet residential charm and excellent urban access.