East Diamante is a submarine volcano located 43 km (27 mi) south of Anatahan in the Northern Mariana Islands of the northwestern Pacific Ocean.

East Diamante is one of two submarine volcanoes in the southern Izu–Bonin–Mariana Arc that have erupted felsic magmas, the other being Zealandia Bank.

[2] Dacite is the primary rock type and generally has a porphyritic texture, with phenocrysts embedded in a matrix of quartz, plagioclase, clinopyroxene, orthopyroxene and iron-titanium oxides.

[2] The summit of East Diamante lies 127 m (417 ft) below sea level and is truncated by an elongated, northeast–southwest-trending caldera.

[1] Argon–argon dating of dacite from inside the caldera has given an age of 20,000 ± 4000 years, indicating that the volcano was active in the Late Pleistocene.