A stroll under the sea. Aquarium Tours

This is a full day on foot from the station, centered on Kawasui Kawasaki Aquarium (カワスイ 川崎水族館), which spreads across the 9th and 10th floors of Kawasaki Le FRONT, a commercial building in front of JR Kawasaki Station. Kawasui is an urban aquarium themed on the beautiful watersides of the world, from the Tama River to Asia, Africa, and the South American Amazon. It is open 10:00-20:00 (last entry 19:00). Admission is 2,200 yen for adults, 1,700 yen for high school students, 1,400 yen for elementary and junior high school students, 800 yen for young children (age 4 and up), and free for age 3 and under (tax included). In the morning, visit Inage Shrine (稲毛神社), about a 10-minute walk from Kawasaki Station. Its sacred great ginkgo tree, said to be about 1,000 years old, and the twelve zodiac statue tour are popular with children. After your visit, return to the station area, then enjoy Kawasui to the fullest in the afternoon. Being indoors, it is a great choice regardless of the weather. Opening hours may change, so check the official website's calendar before you go.

A one-day course to savor the sea and nature in full on the Kannonzaki cape jutting into Tokyo Bay. The main stage, Kannonzaki Nature Museum (観音崎自然博物館), is a museum where you can learn about the nature of the Miura Peninsula and Tokyo Bay through hands-on experience. Open 9:00-17:00 (last entry 16:30); admission is 600 yen for adults (16 and over) and 400 yen for elementary and junior high school students. Closed Mondays (the following day when Monday is a holiday), but open every day in July and August. The whole cape is Kenritsu Kannonzaki Park (県立観音崎公園), free to enter, with sandy beaches, rocky shores, and green walking trails. In the morning, walk the park's seaside and climb Kannonzaki Lighthouse (観音埼灯台), Japan's first Western-style lighthouse, for a sweeping panorama of Tokyo Bay. In the afternoon, spend quality time with the tidepool creatures at the museum. Sea breezes, history, and wildlife watching all in one — a do-it-all day that is quintessentially Yokosuka.

Enoshima Aquarium (新江ノ島水族館) stands facing Sagami Bay, with views of Enoshima and Mt. Fuji. From the great Sagami Bay Tank where 8,000 Japanese sardines swim, to jellyfish exhibits and dolphin shows, this signature aquarium of Kanagawa is packed with more highlights than you can see in a single day. Admission is 2,800 yen for adults, 1,800 yen for high school students, 1,300 yen for elementary and junior high school students, and 900 yen for young children (age 3 and up). Opening hours vary by season, and last entry is one hour before closing. This classic course spends the morning strolling around Katase Beach and Enoshima Benten Bridge from Katase-Enoshima Station to savor the sea air, then devotes lunchtime through the whole afternoon to the aquarium. Stroller rentals and restrooms are well provided, so it is a safe choice even with small children.

Sagami River Fureai Science Museum Aquarium Sagamihara (相模川ふれあい科学館 アクアリウムさがみはら), located in Suigo-Tana on the banks of the Sagami River, is a freshwater aquarium known for its Flowing Aquarium, a 40-meter tank recreating the Sagami River from its upper reaches to its mouth. It is open 9:30-16:30 and closed on Mondays (open if the Monday is a national holiday, and open during school vacation periods). Admission is family-friendly: adults (high school and older) 450 yen, elementary and junior high students 150 yen, seniors 65 and over 220 yen, preschoolers free, and elementary and junior high students living in Sagamihara City also free. In the morning, enjoy river play and a stroll on the Sagami River riverbed at the foot of Takata Bridge, then visit the museum in the afternoon. A river-filled one-day course where the river before your eyes connects with the river inside the tanks. Parking and restrooms are available.