Wan Tsai is a peninsula between Hoi Ha Wan and Long Harbour in north-western Sai Kung Peninsula, Hong Kong. With a narrow neck, Lan Lo Au between Nam Fung Wan and an unnamed bay of Hoi Ha Wan connecting to mainland of Sai King Peninsula, Wan Tsai is hilly with two hills Tai Leng Tun and Nam Fung Shan. Its north tip is Ocean Point (Kwun Tsoi Kok). East of the peninsula finds the Grass Island.
The peninsula was a restricted area. From late 1999, it is opened for public and The Scout Association of Hong Kong had organised a Jamboree for all Hong Kong and international Scouts on the island for a week between 1999 and 2000 to celebrate for the millennium. Another Jamboree was held the following year in 2001 for celebrate 90 years of Hong Kong Scouting.
Since 1996, the peninsula is the Wan Tsai Extension of Sai Kung West Country Park. Facilities are available for camping.The place is reachable by ferry from Wong Shek Pier in Wong Shek at the north shore of the Sai Kung Peninsula