Sanya Visa Policy
From 1988, Sanya and Haikou introduced a “visa on arrival” policy. This policy was introduced in order to support Hainan’s rapid development and its rising international status as a holiday Island. From January 31st 2010, Hainan introduced a visa free policy to 26 countries, these countries included: Japan, Singapore, Malaysia, Thailand, Republic of Korea, Philippines, Indonesia, Germany, UK, France, Austria, Italy, Russia, Switzerland, Sweden, Spain, Netherlands, USA, Canada, Australia, New Zeeland, Finland, Denmark, Norway, Ukraine, Kazakhstan. However this policy was only valid for the tourism field.
1.South Korean, Russian and German tourists were eligible to visit Sanya without a visa if they traveled in groups of at least two or more people and were permitted to stay in Sanya for up to 21 days.
2.The rest of the 21 countries, including Japan and Singapore were eligible to visit Sanya without a visa if they traveled in groups of at least five or more people and were permitted to stay in Sanya for up to 15 days.
more in http://www.horizontravelsanya.com/Sanya_Hainan_China_Introduction_Views.html