If you got to Kamakura early enough and have enough energy left then it’s worth taking the rest of the day to Enoshima. Enoshima is a small island off the coast connected by a bridge. It offers really nice views, shrines, a park, caves to explore and an observation tower.
From Kamakura, you can access Enoshima on the Enoden train. Enoden is a famous train a long the coastline that is often seen in many movies, TV shows, dramas, animes and manga.
Enoshima is divided into a yacht harbor accessible to motorized traffic and a forested hill which can only be explored on foot (and paid escalators) and contains most of the sights. Several shrine buildings, collectively known as Enoshima Shrine, are found around the island and are dedicated to Benten, a popular goddess of good fortune, wealth, music and knowledge. Benten is believed to have created Enoshima before subduing a five headed dragon that had been terrorizing the area.
An interesting aquarium and some of the closest beaches to Tokyo are located on the mainland just off Enoshima. The beaches on either side of the island can become very crowded with sun bathers and swimmers during the summer holidays in July and August, while the long stretches of beach that continue to Chigasaki in the west and Kamakura in the east are popular surfing spots.
Visitors to Enoshima should consider purchasing the Enopass, a combination ticket that includes admission to the island's main attractions (garden, observation tower, caves) and use of the escalators for 1000 yen. The pass provides additional discounts on admission to the Benten Statue, the Enoshima Spa and the aquarium as well as on purchases at dedicated shops and restaurants. The Enopass can be purchased at tourist information desks and the escalator ticket office.
You can also go inside caves (may be closed some days due to weather or water ocnditions) and explore the cave using a candle they give you.
Partial Summary Credit: Japan Guide