These strange rock formations off of the coast of Marabut are definitively worth a look. Carved over the centuries by the strong waves of the Pacific ocean, the rocks are quite impressive. The rocks, made of karst limestone, rise from the sea only a few hundred meters away from the shore, resembling the ones near Krabi in Thailand or the ones in Halong Bay, in Vietnam. The best way to see them is to rent a kayak or a boat from Caluwayan Beach Resort.
Some of the formations host picture-perfect white-sand beaches. Perfect for a swim or sunbathing, especially with the beaches usually being deserted. The marine fauna and flora are also beautiful, with some nice reefs for snorkeling.
Marabut can be done as a day trip from Tacloban, there are plenty of vans and buses going this way. The last trip back is around 4 pm. You can also visit nearby Sohoton Natural Park on the same day.
Most of the rock formations are located near Caluwayan, there's no need to go all the way to Marabut city. As I said, there's a resort there where you can rent a boat. Room rates at Caluwayan Beach Resort start at 2200 pesos per night and the food there is pretty expensive (about 300 pesos per meal).
Kayak rental is 200 pesos per hour. Pump boats cost 500 pesos per hour, good for 4. Entrance fee is 25 pesos. One hour is enough to see most of the rock formations unless you also want to snorkel or stay a bit at one of the beaches.
To reduce the cost you might want to try negotiating directly with a fisherman in one of the villages nearby.