Premium Only

Oze National Park

Ozenational parkwetlandhikingmizubasho

Gunma · Katashina

36.8794°N, 139.2747°E

Oze National Park sits at 1,400-1,600 meters elevation on the Gunma-Fukushima-Niigata border, a high wetland plateau where boardwalks cross marshes that stretch 6 kilometers between mountain ridges. The Ozegahara Marsh is Japan's largest highland wetland — a flat expanse of grass and shallow ponds where wildflowers bloom in waves from May through August. No roads penetrate the park, no cars, no buildings beyond mountain huts. Wooden boardwalks keep hikers off the fragile ground, threading through the marsh in long straight lines that vanish into the distance.

The park's signature flower is mizubasho (Asian skunk cabbage), white petals rising from ankle-deep water in late May and early June. When thousands bloom simultaneously the marsh turns white and green, backed by snowy peaks that still hold winter's snow. The image is famous in Japan — postcard-perfect, the kind of scene that makes people book buses months in advance. Getting here requires commitment: 3-hour bus rides from Tokyo, then another bus to the trailhead, then hiking 90 minutes to reach the marsh. Most people stay overnight in mountain huts (¥9,000 with meals), because day-tripping means 14 hours of travel for 4 hours on the trail.

Essential Information

Opening Hours

Park access: open 24/7 during season | Trailhead buses: first departure 5:00 AM from Oze parking areas | Mountain huts: check-in from 3:00 PM

Closed: Park: closed November–April (snow) | Open season: May–October | Mountain huts may close October after foliage season

Entrance Fee

Park entry: free | Mountain huts: ¥8,000–10,000/person (2 meals) | Shuttle bus to trailhead: ¥980 one-way | Toilet donation: ¥100/use at trail junctions

Best Season

Late May–early June (mizubasho white flowers) | July–August (nikko-kisuge yellow lilies) | September–October (autumn colors + alpine flora)

Visit Duration

Full day (7–9 hours round-trip day hike) | Overnight recommended (13 hrs travel + 4 hrs hiking = exhausting as day trip)

Getting There

Access Information

Oze National Park: Access via Hatomachi Pass (鳩待峠, Gunma side) — 3-hour bus from Tokyo to Oze Koen/Oshimizu, then shuttle bus to trailhead (total ¥3,500-4,500). Day-hike: 8-10 hours round-trip. Overnight hikes: mountain huts ¥8,000-10,000 (includes 2 meals). Best season: late May-June (mizubasho bloom), July-August (nikko-kisuge lilies), September-October (autumn colors). Park closed November-April (snow).

Detailed Access & Timing

Premium

Nearest Station

No train access — Oze Koen Bus Stop via highway bus from Jomo-Kogen Station (JR Joetsu Shinkansen, then shuttle bus 3 hrs total from Tokyo)

Travel Time

From Tokyo Ueno: 3 hrs by highway bus (Kanto Expressway Bus, ¥3,500 one-way) to Oshimizu parking | From Jomo-Kogen Shinkansen: 70-min shuttle bus to trailhead (¥1,500)

How to Get There

Highway Bus (recommended): Kanto Expressway Bus from Tokyo Ueno/Shinjuku to Oshimizu (3 hrs, ¥3,500 one-way). Reserve months ahead for peak bloom season. Shinkansen + Shuttle: JR Joetsu Shinkansen to Jomo-Kogen, then Kanto shuttle bus to Hatomachi Pass trailhead (70 min, ¥1,500 one-way). Book shuttle seat in advance during May–June. Car: Drive to Oshimizu parking (Route 401, 3 hrs from Tokyo) but parking fills before 6 AM during peak bloom — overnight parking required.

Best Time to Visit

Weekdays in late May for peak mizubasho with half the weekend crowd. Start hiking by 7:00 AM to finish before afternoon thunderstorms (common after 2:00 PM in summer). Reserve mountain huts 1–2 months ahead for May–June dates.

Crowd Avoidance Tips

Peak bloom weekends (late May–mid-June) draw 1,000+ hikers per day — trailhead buses fill before 8:00 AM. Arrive at parking/bus stops before 6:00 AM on peak weekends. Weekdays have manageable crowds. Post-bloom summer (July–August) is significantly less crowded.

Parking Information

Oshimizu Parking (main): ¥1,500/day (no overnight). Hatomachi Pass parking: closed to cars during peak season (May–October) — mandatory shuttle from Oshimizu. Arrive before 5:00 AM on peak weekends to secure parking space.

Insider Guide

Premium

**Standard route:** Most people hike Hatomachi Pass to Ozegahara Marsh (90 minutes downhill through beech forest), loop the boardwalks around the marsh (2-3 hours of flat walking), then climb back to Hatomachi Pass (2 hours uphill). Total time: 7-9 hours including breaks. You can day-hike this if you start early — leave Tokyo at 6:00am, catch buses to the trailhead, hike, then reverse the process to arrive back around 20:00. It's a long day. Easier option: book a mountain hut like Yamanohana-goya (¥9,000 with dinner and breakfast), stay overnight, hike out the next morning. Huts need reservations 1-2 months ahead during bloom season, less advance notice off-season. **Mizubasho timing:** The white flowers bloom late May through mid-June, with peak lasting about two weeks. Exact timing shifts a week either way depending on when the snow melts. Check the Oze Preservation Foundation website (oze-fnd.or.jp) for real-time bloom updates starting in early May. Weekends during peak bloom see 1,000+ hikers; weekdays cut that number in half. The huts fill completely during bloom — if you miss the booking window, you're day-hiking. **Summer flowers:** After the mizubasho fade, nikko-kisuge (yellow day lilies) bloom in July and August, turning the marsh from white to golden. August brings smaller flowers — kinkouge (marsh marigold), alpine asters, gentians. Summer weather is warm (20-25°C) but afternoon thunderstorms roll in after 14:00 most days. Start hiking by 7:00-8:00 to finish the loop before the lightning starts. **What to bring:** Hiking boots are essential — the boardwalks get slick when wet and some sections are uneven. Pack rain gear (weather changes in 20 minutes up here), sun protection (no shade on the marsh), 1-2 liters of water, snacks, and lunch. There's no food for sale once you enter the park; the last shop is at the trailhead. Bear bells are recommended because black bears live here, though encounters are rare. Cell service is nonexistent. Toilets exist at major trail junctions (¥100 fee, bring coins). The park has strict pack-in pack-out rules — no trash cans anywhere, carry everything out.

View on Google Maps