The deal includes Scarlets home, away and European shirts and kits, all of which will be available to the region's supporters through the Scarlets retail store.
Rhino Rugby is the UK's leading rugby equipment and apparel manufacturer and is a supplier to the Welsh Rugby Union and England rugby as well as Wasps, Bath, Edinburgh and Northampton Saints. Rhino was an official supplier to the British & Irish Lions Tour to South Africa in 2009.
Scarlets Commercial Director Rupert Moon said: "We are really pleased to have Rhino Rugby on board. With so many years as a leading rugby brand and supplier to top flight clubs, they link well with our heritage and stature within the rugby community as well as with our ambitions to continue building a strong, iconic Welsh rugby brand.
"The new-look kit reflects the modern rugby era as well as pride in our true Scarlet colour and with it our long-standing history. For any supporter it looks stylish, practical and professional. We are sure that our followers will like the new-look kit and hope they will support us by showing their true colour with pride this season - Scarlet!
The main sponsor on the shirt is WRW Adeiladwaith. Other sponsors include INA Bearings, Coleg Sir Gâr and Meridian.
Rupert Moon said: "It is an honour to have these companies on board and it is great to see WRW flying the flag for the Welsh language in the region."