[1] In 1894, he journeyed to India as part of Annie Royle Taylor's Tibetan Pioneer Mission, which would fail within a year.

In 1896, together with Theo Sørensen, he traveled to Darjeeling and Kalimpong in the Himalayas near the borders of Tibet as a missionary for the China Inland Mission, where he studied Tibetan religion and customs.

[2] After their language studies Amundsen attempted to travel from there to Lhasa in Tibet but was halted eight days journey short of the "forbidden city."

His wife Petrea Ness (1862–1928), from Mandal, Norway, was also a missionary and accompanied him on his trips to China and Tibet.

[3][4] During the Boxer Rebellion in 1900 he left China for Darjeeling,[1][5] but in 1903 he returned and then worked in Yunnan for the British and Foreign Bible Society until 1911.