Tonggu Ridge is famous locally for its great views up and down the coast from the top, especially of the moon-shaped beach at Yue Liang Wan’s beach. It’s 3km to the top; there’s a shuttle bus (¥20 round trip, 9am to 6pm) or you can hike along the road (though this is not so pleasant with the buses going up and down).
To get to Tónggǔ Lǐng, take a bus from Haikou’s east bus station to Dongjiao (¥23, 1½ hours, five daily), and then transfer to a minibus bound for Longlou (龙楼镇, Lónglóu Zhèn; ¥6, 30 minutes, hourly). At the Longlou bus stop, sānlúnchē (pedicab) drivers wait to take tourists the last 8km to the ridge; expect to pay about ¥20. Alternatively, you can cycle here from Dongjiao Coconut Plantation in about two hours.