Captain Thomas James (1593 – 1635) was a Welsh sailor, navigator and explorer, who set out to discover the Northwest Passage, the hoped for ocean route around the top of North America to Asia.

When the Society of Merchant Venturers of Bristol appointed him to lead their expedition in 1631, they referred to him as skilled navigator and mathematician, suggesting he was both experienced and respected.

He left of 1 July 1632, took 3 weeks to exit James Bay, worked his way north through ice, reached the mouth of Hudson Strait, went north into Foxe Channel only to 65°30', turned back and reached Bristol on 22 October in a vessel that was barely seaworthy.

[4] He named the southern coast of Hudson Bay the "New Principality of South Wales", after his native land.

Some critics have opined that Samuel Taylor Coleridge's work The Rime of the Ancient Mariner was inspired by James' experience in the Arctic.