By the time Mimosa made the voyage she was already past her prime, having been built in 1853 at Hall's shipyard in Aberdeen. She had not been designed to carry passengers, but had been converted for the purpose. The cost of fitting provisioning and chartering the ship was £2,500 and the passengers paid £12 per adult or £6 per child for the journey. Before the voyage the emigrants assembled at various points, not always their places of origin, to prepare for the journey, including Aberdare, Birkenhead and Mountain Ash. Mimosa sailed from Liverpool, England on 28 May 1865 to Patagonia, South America with a group of about 153 passengers with Captain George Pepperell and a crew of 18. Thomas Greene, an Irishman from Kildare, had been appointed as ship's surgeon. They landed on 28 July 1865 and named their landing site Porth Madryn. They were met by Edwyn Cynrig Roberts and Lewis Jones who had already arrived in Patagonia in June 1865 to prepare for the arrival of the main body of settlers. Their aim was to establish a Welsh colony which would preserve the Welsh language and culture. The proposed site for the colony was in the Chubut River valley. On 15 September 1865 the first town in the Chubut colony was named Rawson, and the settlers went on to build the settlements at Gaiman and Trelew.
Welsh emigrants aboard ''Mimosa''
The exact number of emigrants who sailed out to Patagonia on Mimosa remains uncertain. Although one of the original settlers, Richard Jones, maintained a register of births, marriages and deaths for many years, most of these original records were lost in the great flood in the Chubut Valley in 1899. In 1875, the Argentine government granted the Welsh settlers ownership of the land which encouraged hundreds of others from Wales to join the colony. In the early 21st century, approximately 50,000 Patagonians are of Welsh descent, of whom around 5,000 are Welsh speakers. The Welsh-Argentine colony, which became known as Y Wladfa, remains centered on Gaiman, Trelew and Trevelin.