Tsubakishima, Desert island and natural monument in Rikuzentakata, Japan.

Tsubakishima is an uninhabited granite island of about 22.4 hectares in the Pacific, roughly 1 kilometre off the Hirota Peninsula of Rikuzentakata, Iwate Prefecture. Its slopes once held a stand of yabutsubaki camellias, now dead, leaving sparse grasses; a lighthouse, the Rikuzentakata Tsubakishima light, stands on the island.

On 28 December 1934 the island was designated a national natural monument together with Aomatsushima as the "Tsubakishima black-tailed gull breeding ground". In 1962 Iwate Prefecture added it to its wildlife protection area "Tsubakishima and Aomatsushima, Rikuzentakata", covering 2 hectares with the whole island as a special protection zone. The island lies about 1 km off the Hirota Peninsula.

The name Tsubakishima means "camellia island", after the yabutsubaki camellias that once grew here; the plants have since died, and only a few herbaceous species remain. Today the island is known instead for its breeding seabirds, with thousands of black-tailed gulls and a few night herons recorded.

Tsubakishima lies about 1 km off the Hirota Peninsula in the open Pacific, and there is no scheduled ferry service, so a boat must be arranged in advance and the crossing timed to sea conditions. The island has no docks, facilities or services, and its slopes are nesting grounds for thousands of streaked shearwaters' neighbours, the black-tailed gulls, so landings are restricted in the breeding season.

The island's name comes from the yabutsubaki camellias that once grew here; they have since died off, leaving only a few herbaceous plants. Today several thousand black-tailed gulls and a small number of night herons nest on the island, and rhinoceros auklets and spectacled guillemots also bred here. A navigation light, the Rikuzen-Tsubakishima Lighthouse, stands on the island.