The number of overnight stays at hotels, cabins and youth hostels rose 9 percent in April, according to figures from Nutek and Statistics Sweden.
Since the turn of the year, the number of guest nights has increased 6 percent compared with the same period in 2007.
Stockholm County tops the list with 2.3 million overnight stays through the first four months of 2008.
Dalarna County in central Sweden comes in second with nearly 1.6 million, followed by Västra Götaland County in western Sweden, which registered about 1.2 million overnight stays.