The January-August period saw the number of tourist arrivals plummet by 47% to almost 2.4 million, while tourist nights dropped by 40% to almost 7.1 million compared to the same eight-month period in 2019, figures released by the Slovenian Statistics Office (SURS) show.
The number of domestic tourists rose by 26% in the eight-month period, with nights they generated rising by 34%.
Foreign arrivals plummeted by 70% in this period, and the nights they generated by 67%, SURS data for January-August show.
The drop in foreign tourists was meanwhile partly offset by domestic tourist, who largely opted to spend their summer holidays in Slovenia.
As a result, the summer season - July and August - saw a mere 16% drop in overall tourist nights to 4.6 million compared to last year's summer tourist season.
More than two thirds of all nights in the two months were generated by Slovenian residents, whose tourist nights rose by 159%.
The number of nights generated by foreign tourists in July-August meanwhile plummeted by 65%.
The bulk of nights generated by foreign tourists in the two months were generated by Germans, yet the figure was nevertheless by 22% lower.
Drops in nights by tourists from other countries were even bigger, standing at -67% for the Dutch and for Italians, at -42% for Austrians and -49% for Hungarians.
Drops by nights generated by Australians, South Koreans, Swedes, New Zealanders, Maltese and Israelis were at more than 95%.
Israelis for instance generated around 128,000 nights in the 2019 summer season as opposed to below 600 this year.
At municipality level, the bulk of tourist nights in July and August were spent in the mountains (1.6 million), on the coast (1.2 million) and in spas (929,000).
Compared to last year's summer season, the sharpest fall in tourist nights was witnessed by the city of Ljubljana (-75%), followed by other urban municipalities (-45%).
Municipalities with spas and on the coast meanwhile reported about upbeat tourist night figures - up by 9% and 4%, respectively.
The coastal municipality of Piran led the way with the biggest number of nights among all of Slovenia's 212 municipalities at 686,000, up 1% from July-August in 2019.
The figures for the second quarter meanwhile show that at least 15% of Slovenia's residents aged at least 15 went on a private trip, a drop of two thirds over the same period last year. A third of around 1.5 million residents who did not go on a trip cited the pandemic as the main reason.
This year's April-June quarter saw the same number of private trips as the January-March quarter, yet considerably fewer than the second quarter last year.
The April-June period has been in recent years a busy tourist period with around a million private trips taking place. This year's figure reached only some 410,000.
An increasing number, or 52%, opted to go on a private trip around Slovenia, whereas Croatia topped the list of destinations outside the homeland (92%).