The city state with 276 square miles has 45,043 tourists per square mile, according to the Telegraph Travel analysis of the United Nations World Tourism Organization (UNTWO)'s global tourism statistics.
Singapore records annual visitors at 12.4 million.
Known for its meticulous urban planning and famously strict regulations against littering, Singapore is always rated one of the world's cleanest cities.
Thanks to its low crime rate and strict laws, Singapore has become one of most popular destinations in Southeast Asia.
Macau topped the list with 1.4 million tourists per square mile, followed by Monaco and Hong Kong.