Residents accounted for 75% of total arrivals at accommodation establishments in May, while foreigners made up for the reminder 25%.
The large majority of foreign visitors (93.2%) came from Europe, the data showed.
Numbers of Romanian tourists traveling abroad rose 6.2% on the year in May.
In January to May, tourist arrivals increased by 9.9% on the year, while overnight accommodations were up 4.7%.