Mikazuki Sea-Park Hotel Katsuura: Day-Use Hot Spring

This is one of the signature onsen resorts on the eastern side of the Boso Peninsula, overlooking Katsuura Bay on the Pacific coast. From the view bath named Hiten no Yu, set about 40 meters above the ground, you can take in an open vista that stretches all the way to the horizon. It is also easy to reach, just a five-minute walk toward the sea from JR Katsuura Station.

Highlights

The biggest highlight is the panoramic top-floor bath Hiten no Yu, built high up in the tower. Below your feet spread the fishing harbor and townscape of Katsuura, and at night the lights of the fishing boats make for a beautiful view. Inside the building there is also the spa dome Aqua Palace you can enjoy in swimwear, so families can spend a whole day here, which is a rare draw.

Enjoying the Seasons

In summer, pair sea bathing at Katsuura Beach with the hot spring. In winter, the outdoor bath feels especially good after the chill of the sea breeze. Katsuura is known for cool summer sea temperatures and a mild climate, so it is comfortable to visit throughout the year.

Access and Basic Information

The address is 820 Sumina, Katsuura City, Chiba. It is about a five-minute walk from Katsuura Station on the JR Sotobo Line, or roughly one hour by car from the Ichihara-Tsurumai interchange of the Ken-O Expressway. The large bath Hiten no Yu is generally open from 15:00 to 24:00 and again from 5:00 to 9:00 the next morning. Day-use bathing is possible, and discounts for nearby residents may be offered. Renting a towel for day use costs a fee of about 330 yen per towel. Availability changes by season, so check the official site in advance.

Practical Travel Notes

The view bath is all about the scenery, so daytime with the horizon in sight or the evening with the fishing lights is especially recommended. To enjoy the spa dome and pool as well, set aside at least half a day. Budget from the low thousands of yen for day-use bathing, or a few thousand yen once you add a meal or the spa. It is within walking distance of JR Katsuura Station, so it is easy to reach without a car, and it combines well with a stroll through Katsuura, famed for its morning market, or the Tomisaki Shrine doll festival in February and March. To avoid crowds, weekdays are the safer choice.

A Quick Tip

The view bath is best just before dawn. Watching the morning sun rise slowly over the Katsuura sea from the bath will give you an unforgettable morning. Staying overnight makes the early hours easy to use, letting you enjoy both the sunrise and the night view.

Practical Information for Your Visit

• Spring quality: Sodium chloride and bicarbonate hot spring
• Indications: Neuralgia, muscle pain, joint pain, frozen shoulder, motor paralysis, joint stiffness, bruises, sprains, chronic digestive disorders, hemorrhoids, sensitivity to cold, convalescence after illness, health promotion, cuts, burns, chronic skin conditions, frail children and chronic women's ailments, among others
• The "Hiten no Yu" large bath with a view: For overnight guests only; day-use bathing is not offered. Available 15:00-24:00 and 5:00-9:00 the next morning, with the sauna open 15:00-23:00. Bath towels are always provided in the large bathhouse
• What day visitors can use is the "Aqua Palace" spa: Weekdays 10:00-17:00 (last reception 16:00); Saturdays and the middle days of long weekends 10:00-19:00 (last reception 18:00). From July 18 to August 30, 2026 it is open 10:00-21:00 (last reception 20:00). The pools may be used until 30 minutes before closing
• Summer restriction: From July 1 to August 31, the Aqua Palace is also restricted to overnight guests
• Day-use admission (revised June 1, 2026): Weekdays 2,200 yen for adults, 1,540 yen for seniors (65 and over) and 1,320 yen for children (age 3 through elementary school). Saturdays, Sundays, public holidays and designated days 3,300 yen for adults, 2,310 yen for seniors and 1,980 yen for children
• Local residents' discount: Residents of Katsuura City, Kamogawa City, Isumi City and Isumi District receive 220 yen off. Proof of address is required
• Towels: Day visitors renting a towel pay 330 yen per person for ages 3 and over
• Swimsuit rental: 550 yen per suit. Children's sizes 80 cm to 150 cm and adult sizes M to 3L. Numbers are limited
• Tattoos: Not permitted in either the large bathhouse or the Aqua Palace
• Private and family baths: None
• With children: Children may use the pools if they wear swim diapers. For bathing, children aged 6 and under may enter with an adult of the opposite sex
• Amenities: Guest rooms are equipped with shampoo, conditioner, body soap and a hairdryer
• Barrier-free access: The hotel is not fully barrier-free, and there are some steps inside the building and in the guest rooms. Wheelchairs are available to borrow, but numbers are limited, so you need to inquire by telephone in advance
• Payment methods: Card payment is accepted (except for some accommodation plans)
• Parking: 200 spaces. For overnight guests it is free for up to 24 hours per night, while day visitors get 3 hours free and pay 200 yen per hour thereafter. The indoor car park has a height limit of 2.20 m
• Access: About a 5-minute walk from Katsuura Station on the JR Sotobo Line, heading toward the sea. By car, it is along the coast road of National Route 128, next to the Katsuura Post Office and opposite the Tona municipal car park. The shuttle service is for overnight guests only
• Location and inquiries: 820 Tona, Katsuura City, Chiba Prefecture (Katsuura Coast), telephone 0470-73-1111
• Time needed: If you plan to enjoy the Aqua Palace, set aside at least half a day. Combined with the Katsuura Morning Market and a walk around town, it makes a full-day itinerary

📚 Sources

The spring quality, indications and contraindications, the hours of the "Hiten no Yu" large bath with a view and its sauna, the fact that day-use bathing is not offered, and the Aqua Palace's opening hours, summer period restricted to overnight guests, day-use admission fees (including the revision of June 1, 2026), local residents' discount and towel rental fee were confirmed on the hot spring and spa pages of the official Mikazuki Sea Park Hotel Katsuura website. The policy on tattoos, the swimsuit rental fee, the absence of private baths, guest room amenities, the conditions for children not yet out of diapers, barrier-free access and wheelchair loans, and payment methods come from the frequently asked questions on the same official site. The address, telephone number, walking access, landmarks for drivers, the number of parking spaces and fees, and the height limit are compiled from the access page of the same official site. Details are subject to change, so please check official information before you set out.