Tate's Cairn Tunnel is a four-lane road tunnel in Hong Kong. Constructed as part of Route 2, it links Diamond Hill, New Kowloon with Siu Lek Yuen, Sha Tin, New Territories East. It opened on 26 June 1991. Its toll plaza is situated on the Sha Tin side, leading to Tate's Cairn Highway, Sha Lek Highway and various local roads. The tunnel joins the Kwun Tong Bypass and is connected with Lung Cheung Road and Hammer Hill Road and several local roads on the Kowloon side.