St. Andrew Strait is a volcano in Papua New Guinea that has had eruptions in historical times.

It consists of a group of Quaternary volcanic cones that are mainly rhyolitic in composition.

The volcanism is curved, suggesting that the volcano has an ancient caldera.

Lou island is the largest eruptive centre of the volcano, with 6 volcanic vents.

A small submarine eruption came from the Tulaman islands on March 28, 1880.