Walk along the southern tip of Miura Peninsula by taking the train to Keikyu's Miurakaigan Station 三浦海岸駅 then bus 海 35 for 20 minutes to Matsuwa Kaigan 松輪海岸. Walk west along the coast for some amazing views of the ocean, similar landscape to Arasaki Park 荒崎公園 and Jogashima Island 城ケ島. Use the Miura 1-day or 2-day train-plus-bus pass 三浦半島1DAYきっぷ to save on transport cost.
As for May, 2018, there's a wooden bridge on the way that's broken due to typhoon so it's not advisable to walk there but it is still possible to cross. It is pretty scary though, especially on a windy day. Make sure you have sensible footwear as you'd be walking on some pretty jagged rocks jumping over puddles of sea water.