Thomas and his wife Jane with their two daughters, Amanda and Jane Elizabeth, sailed from New York to San Francisco, California in 1846 on the ship Brooklyn. They remained in California until after the gold discovery in January 1848 and then traveled to Utah. Both Thomas and Jane were re-baptized at Salt Lake City on 29 April 1849 and Thomas' name appears in the records of the Utah Territorial Militia in Salt Lake City in February 1850. It was also here in Deseret that Thomas and Jane received a mission call to the Society Islands for the Church of Jesus Christ of Latter-day Saints in 1850. This same year the Tompkins family arrived in Tahiti early enough for Jane to give birth to a son they named Isaiah; he was born in October 1850. His death date and place of burial are unknown. At the end of their Polynesian mission the family returned to Utah, but later moved to San Bernardino, California. This is where Jane died and where Thomas is buried.